The Corpus of eighteenth-century texts: 
Towards the construction of the Diachronic Corpus of Russian

Svetlana Savchuk
Institute of Russian Language 
Russian Academy of Science
savsvetlana@mail.ru

Abstract

The paper presents the results of a project aimed at the creation of a sub-corpus of 18th-century Russian texts within the Russian National Corpus. The main problems concerned with text preparation and morphological annotation and prospects for Corpus development are discussed.
As far as the corpus of 18th-century Russian texts is being constructed at the base of the technology developed for the RNC, it has two special features. 1) The electronic versions of texts included in the corpus reproduce the printed or manuscript texts in the orthography of the 20th century. 2) The morphological annotation is performed automatically by the parser developed for modern Russian texts and based on the grammar dictionary of modern Russian.
The principal benefits of this method are as follows. 1) The Corpus of the 18th-century Russian texts is a module in the RNC supplied with the same types of annotation and compatible with the other diachronic parts of the RNC (texts dating from 1800 to 1950) as well as with its main part of modern Russian texts. 2) Errors of morphological tagging, especially the list of the ‘unknown’, unidentified word forms give essentially valuable material for the analysis of the orthographic, phonetic and grammatical variation in the 18th-century language.

1. Introduction

Initially the RNC was created as a corpus of the contemporary Russian language, which aim was to reflect the contemporary language usage in its functional variety. However, we immediately had to face the problem of defining this ‘contemporary usage’. Should we have included the texts of the end of the 20th century and the beginning of the 21st century only? Or should we have taken into account that the history of the literary language considers the ‘contemporary’ language as the language of the period ‘from the time of Aleksandr Pushkin (that is the beginning of the 19th century) to the present day’?
It became clear from the very beginning that the corpus would provide a perfect opportunity to explore the history of the literary language. It accumulates a great amount of data and has an effective search engine which is very fast and can work with a large quantity of texts. It enables us to track any historical changes in morphology, syntax or semantics. 
Therefore the corpus started to develop in two directions: on the one hand, there is a corpus of the current texts of the 20th and 21st centuries, on the other hand – there is a corpus of the earlier texts of the 19th century and the first half of the 20th century.
At present the main corpus of the RNC contains the following:
•	Corpus of modern written texts, 1950–2008 – 97,4 millions tokens
•	Corpus of spoken language - 8,5 millions tokens 
•	Corpus of written texts, XVIII – the first half of the XX – 68 millions tokens
•	Texts of the 1st half of the XXth – 40 millions tokens
•	Texts of the XIXth century – 26 millions tokens
•	Texts of the XVIIIth century – 2,6 millions tokens
Specialized corpora
•	Poetic corpus 
•	Dialect corpus 
•	Parallel aligned corpus 

2. The Corpus of 18th-century texts: composition and main parameters

How was the idea of the Corpus of 18th-century texts born? Many authors who played a significant part in the development of the contemporary literary language, such as Karamzin, Derzhavin, Krylov and the others, launched their careers in literature in the end of the 18th century. Consequently, their texts were already presented in the corpus. The last step was to start creating the corpus of the 18th century texts which would present the history of the contemporary literary language.
The corpus of the 18th century texts nowadays contains more than 2.6 million tokens in the form of about 800 full texts dating from 1700 to 1800. These texts cover main functional spheres (fiction, journalism, educational and scientific, official, religious, and everyday life spheres) and represent a wide range of text types, for example, novels, plays, handbooks, law, documents, sermons, diaries, private and official correspondence, etc.). In addition to the basic selection of prose there is a supplementary part of the corpus (about 700 thousand tokens) - 18th-century poetry as a component of the Poetic Corpus within the RNC. 
Fiction is represented by authors that exerted great influence on forming of the literary language: N.M. Karamzin, I.A. Krylov, N.I. Novikov, A.A. Nartov, A.N. Radishchev, D.I. Fonvizin, M.D. Chulkov. Poetry of 14 authors (among them I.F. Bogdanovich, I.S. Barkov, G.R. Derzhavin, I.I. Dmitriev, A.D. Kantemir, I.A. Krylov, M.V. Lomonosov, A.P. Sumarokov, V.K. Trediakovsky, I.I. Hemnitser, M.M. Heraskov, etc.) is included in the Poetic Corpus. Journalism is represented first of all by satiric articles by N.I. Novikov, disputes between N.I. Novikov and Catherine the Great, social and political articles and essays by D.N. Fonvizin, A.N. Radishchev, a philosophic treatise by G. Skovoroda, a lampoon of M.M. Shcherbatov and memoirs of A.T. Bolotov, P.A. Levashov, J.P. Shakhovskoj. Educational and scientific sphere includes works by A.N. Radishchev on economy, law, history, politics; philological writings by M.V. Lomonosov, D.N. Fonvizin and N.I. Novikov; works of historian V.N. Tatischev. Official sphere is represented by different memos, petitions, testaments, projects, edicts, army regulations. Everyday life sphere — private letters by N.M. Karamzin, A.N. Radishchev, D.N. Fonvizin, I.F. Bogdanovich, A.A. Boratynsky, N.L. Lvov, G. Skovoroda, A.V. Suvorov, diaries of S.A. Poroshin. Church and theological sphere that is works by a brilliant representative of Russian religious eloquence Platon (Levshin) and Feofan Prokopovich.
The quantitative distribution of texts in the Corpus according to main spheres of functioning is shown in Table 1.

Sphere of functioning	Persentage	
Everyday life	5	
Official	11	
Journalism	24	
Educational and scientific	17	
Fiction	24	
Religious	19	
Table 1. The distribution of 18th-century texts according to spheres of functioning
The texts of the corpus are distributed to 3 periods according to the periodization accepted in the history of the Russian language (Vinogradov, 1978):
•	Early Eighteenth-Century Russian Prose (1700-1730) – 4%, 
•	Middle Eighteenth-Century Russian Prose (1731 -1780) – 59%, 
•	Late Eighteenth-Century Russian Prose (1781-1799) – 37%.
The Сorpus of 18th-century Russian texts is supplied with three types of annotation. Metatextual annotation refers to a whole text and includes information regarding author’s name, age, sex, text characteristics (creation date, sphere of functioning, text type, domain, etc.), publication format, bibliographical sources, and so on. A full set of characteristics for a given text as it is represented on the page of search results is shown below. 
Author	М. Д. Чулков	
Gender	муж	
Birth date	1740	
Title	Пересмешник, или Славенские сказки	
Date of creation	1766-1768	
Domain	художественная	
Genre	фантастика	
Time and place	ирреальный мир	
Тype	сказка	
Style	нейтральный	
Sentences	589	
Words	13987	
Audience age	н-возраст	
Audience educational level	н-уровень	
Audience size	большая	
Medium	книга	
Source	Волшебно-богатырские повести XVIII века. -- М.: Советская Россия, 1992	
Date of publication	1992	
Publication	Волшебно-богатырские повести XVIII века	
Publiching house	«Советская Россия»	
Subcorpus	корпус 18 в.	
Tagging	manual	

Morphological information is assigned to a word-form and consists of four groups of tags:
1. Lexeme (a dictionary form of the lexeme and the part of speech to which it belongs). 
2. A variety of the lexeme's grammatical features, known as word-classifying features (for example, gender for nouns and transitivity for verbs). 
3. A variety of the wordform's grammatical features, known as word-altering features (for example, case for nouns and number for verbs). 
4. Information concerning non-standard forms of the word-form, orthographic variations, etc.
Semantic annotation is performed automatically by the Semmarkup program (by A.E. Poliakov) which uses the Semantic dictionary of the Corpus. There are three groups of tags assigned to words to reflect lexical and semantic information: 
1. Class (a name, a reflexive pronoun, etc.) 
2. Lexical and semantic features (a lexeme's thematic class, indications of causality or assessment, etc.) 
3. Derivational features (a diminutive, an adjectival adverb, etc.). As a result most words in a text are tagged with a number of semantic and derivational parameters such as ‘person’, ‘substance’, ‘space’, ‘movement’, ‘diminutive’, etc. It is possible for a word to be assigned characteristics along several different parameters. (RNC
The corpus is available on open access on the website ruscorpora.ru. Search on the corpus is provided by the Yandex.Server system.
The corpus, yet still small, is already used in scientific researches and in lexicography, including the compiling of the Russian dictionary of the 18th century (Savchuk&Grishina, 2008). So we can say that the first stage of creating the corpus is finished by now. 

3. The Corpus of 18th-century texts: problems of optimization

In the second stage the most important goal is to analyze the problems emerged during the composing of the corpus. It would help to optimize this process and simplify the use of the corpus. These problems concern not only the corpus of the 18th century, but also the diachronic part of the RNC in whole. However, it is the 18th century corpus that has been chosen as a pilot project for the adjustment of the preparation of texts. Why? 
Firstly, this corpus is still not big (2.5 million), so it is not difficult to analyze and edit it. 
Secondly, there is much more difference from the current language state presented in this corpus, than in texts of subsequent period. Therefore, all the corrections made for the 18th century texts would later work for the 19th century texts and the texts of the beginning of the 20th century. For example, variant forms of instrumental case of nouns, adjectives and pronouns such as ‘думою’ (now ‘думой’), ‘мыслию’ (now ‘мыслью’), ‘верною’ (now ‘верной’), ‘своею’ (now ‘своей’), and the other predominant forms of the 18th century were widespread in the 19th century language as well, and some of them are still used in modern poetry (Savchuk et al, 2007).
From the point of view of preparation the 18th century texts have a lot in common with other types of texts – dialect, spoken colloquial or electronic texts. All these texts have many deviations from the standard language. Therefore some of the solutions would be common for all such corpora (Rayson et al, 2007; Baron, 2009; Savchuk & Sichinava, 2009). But, on the other hand, the historical corpus is specific, because these deviations are qualitatively different from the standard language and from the other non-standard varieties of Russian.
As far as the corpus of 18th-century Russian texts is being constructed at the base of the technology developed for the RNC, it has two special features.

3.1. Non-standard orthography

The first one is concerning the orthography. The electronic versions of texts included in the corpus reproduce the printed or manuscript texts in the orthography of the 20th century. It means that for modern editions of the 18th-century texts spelling is meet the requirements of modern orthographical rules (accepted in 1956). For pre-revolutionary editions changes in spelling are made according to the reform of orthography in 1918.
The following example illustrates this point. Below is given the page of the black-letter book “Yunosti chestnoye zercalo”, printed in 1717; the OCRed version of the same fragment, and the same text, prepared for the Corpus.

OCRed text	The same text, prepared for the Corpus	
Младыи человѣкЪ всегда имѣетЪ сЪ благочестными и добродѣтелными людми обходїтїся, отЪ которыхЪ бы онЪ добру научїтца могЪ. Также и сЪ такїми  людми которые и честное имя и непорочное жїтїе имѣютЪ. А отЪ такїхЪ, которые легкомысленно и sлочестно живутЪ, бѣгать яко бы отЪ яду или лютого мору.	Младый человек всегда имеет с благочестными и добродетелными людми обходитися, от которых бы он добру научитца мог. Также и с такими людми которые и честное имя и непорочное житие имеют. А от таких, которые легкомысленно и злочестно живут, бегать яко бы от яду или лютого мору.
	
If you compare two versions, you can see that all the changes have been made according to the reform of 1918, they are marked with red letters (e instead of ѣ, и instead of ї, Ъ at the end of the words is taken away). The other orthographic features (in italics, marked with blue letters) haven’t been changed.

3.2. Morphological annotation of historical texts

The second peculiarity of the 18th century corpus is its linguistic annotation, especially morphological. There are three variants of marking earlier texts.
1) Manual annotation. The results are great, but this method is very expensive and slow. It can be used only for compiling small or ‘gold standard corpora’. Within the RNC this method was employed for compiling the Dialect corpus (200-250 thousand tokens in 3 years) and for making the disambiguated subcorpus (about 6 millions tokens in 6 years).
2) Automatic annotation using the tagger based on an electronic dictionary of 18th-century language. But we have no grammar dictionaries of the Old Russian, ready for use, and explanatory dictionaries cannot provide enough morphological data in relation to the languages with well-developed inflexion system. 
Before marking the earlier texts the lemmatizer based on an electronic dictionary should be created. There is no such dictionary of the Russian language. That is why it may be compiled with the use of the 18th century dictionaries, the Academic dictionary, Dahl’s dictionary, dictionaries of rare words, etc. But this is a problem which has not been set yet (the dictionary of Lomonosov’s texts is still under development, the contemporary dictionary of the 18th century has only been compiled up to the ‘О’ letter, the dictionary of the first half of the 19th century is only being planned). We, on the contrary, think that the corpus would speed up conducting the researches in historical lexicography. Particularly, we are planning on compiling the electronic dictionary of the 18th century while making the corpus.
3) The use of the modern tagger with the further analysis of the markup results. It was the method used for morphological markup of the diachronic corpus. Similar solutions were made in some other projects (Hauser, 2007; Rayson 2007a, b; Bennet, 2009; Meyer, 2009).
The morphological annotation in the 18th century Russian corpus is performed automatically by parser developed for modern Russian texts and based on the Grammatical dictionary of Russian by Zaliznyak (1977; 2003). Standard word-forms presented in dictionary are recognized by the parser and tagged as norm. Non-standard forms which are not presented in the dictionary and in corpus lexicon get the ‘bastard’ mark and hypothetic parsing. Tagging and lemmatization of approximately 10 percent of text volume are checked manually.
Why has this annotation method been chosen? Is it appropriate to use the modern methods of morphological marking for diachronic corpora?
The following text data support this solution. The table shows the percentage of non-standard forms in different subcorpora of the RNC. If we compare data, we’ll see that the number of non-standard word forms in the 18th century texts exceed those in written texts. But these differences are not that significant in comparison with dialect and electronic texts.

Sub-corpus	Total volume	Non-standard word forms	Percentage 	
XVIII	2,6 Mw	123315	4,6%	
XIX	26 Mw	611373	2,3%	
XX-1	40 Mw	967964	2,4%	
XX-2-journalism	42,7 Mw	908358	2,2%	
XX-2-fiction	38,5 Mw	562622	1,5%	
XX-2-e-comm	1,3 Mw	80621	6,1%	
XX-2-dialect	138961	9045	6,5%	
Table 2. The distribution of non-standard forms in subcorpora

The detailed results for the 18th century texts are presented in Table 3.
Sub-corpus	Total volume	Non-standard word forms	Percentage 	
1700-1730	95049	6578	6,9%	
1731-1760	337508	30317	9,0%	
1761-1780	1073128	52382	4,9%	
1781-1800	1273829	40657	3,2%	
Table 3. The distribution of non-standard forms in subcorpora of the Corpus of 18th century texts

It can be seen that the 18th century texts are heterogeneous in terms of specificity. The earlier texts are full of non-standard words, whereas the later texts are the same as of the 19th century and the beginning of the 20th century. The texts of the middle of the 18th century have a great amount of off-lexicon words, because this part of the corpus presents a lot of long religious texts by bishop Platon, which are full of Church Slavonic, and the texts by the historian Tatischev with a lot of encyclopedic information – proper names, place names, names of tribes and nations, historic events. Most of these are not presented in the corpus electronic dictionary.
Consequently, we should choose different methods for the texts with different amounts of non-standard forms presented.

3.2.1. Orthographical normalization

Preliminary orthographical normalization is required for the texts of the beginning of the 18th century. It is especially true for handwritten texts which were not supposed to be published: they have never been edited. More than 30% of deviations can be found in such texts. As T. Pilz notes, a high percent of non-standard spellings in historical texts is documented for numerous European languages, among those German, Dutch, English, French and Slovenian (Pilz, 2007). The fragment of the letter given below illustrates high degree of non-standard spellings in a handwritten Russian text of the beginning of the 18th century.

To I.I. Kireevsky from V. Grigoriev (28 May 1714)

Гсдрю{государю*} Ивану Ивановичу московскова{московского*} двора твоего дворник Василеи{Василий*} Григоревь{Григорьев*} челом бьет в доме твоемь{твоем*} все дал бгь{бог*} здорова{здоровья*} да буди тебе ведома{ведомо*} что бил челомь{челом*} тебе Афонасеи{Афанасий*} Михаиловь{Михайлов*} снь{сын*} Растовскои{Ростовский*} чтобы ему жит{жить*} на твоемь{твоем*} дваре{дворе*} в горницы{горнице*} и нне он Афонасеи{Афанасий*} приехал жит{жить*} на двор твои{твой*} сам третеи{третий*} з{с*} двемя{двумя*} бабами и живет в горницы{горнице*} …
#Overleaf# Гсдрю{государю*} Ивану Ивановичю{Ивановичу*} ЧГД1 г маия{мая*} въ КИ де подал к{крестьянин*} Liевон{Левон*} Fiедоrов{Федоров*}

All cases of substandard spelling are marked: abbreviations, misspellings, archaic spellings, archaic morphological forms, obsolete words. All of them would be misinterpreted and, therefore, would be parsed incorrectly. The general number of such words in this text is more than 34%. After manual or automatic analysis all such deviations get their standard equivalents which would be lemmatized later with grammar features attributed to the whole complex. As a result we’ll get original word forms of the 18th century with the correct grammar parsing. You would get the same if you input these words in the corpus lexicon and had them identified correctly by the lemmatizer.

3.2.2. Enriching the corpus lexicon

It seems that preliminary manual normalization is not required for the texts of the second half and the end of the 18th century, because there are not more that 5-10% of non-standard words in a text. It is more effective to expand the vocabulary of the corpus lexicon. This work is now in progress. We are analyzing the vocabulary database of the corpus. As a result we expect to create a module of the electronic lexicon which would be aimed at analyzing the texts of the 18th, 19th and the first half of the 20th century.
What is going to be included in the lexicon?
We are going to receive this information analyzing ‘bastards’ – I recall that these are non-standard word-forms beyond the corpus lexicon with hypothetic identification. We began this analysis with the most frequent words and distinguished several classes of the bastards.
1.	The first group can be named ‘the encyclopedic part of the lexicon’. It consists of proper names - personal names, place names, the names of historical events - and their derivatives: Исайя, Людовик, Невтон (norm Ньютон ‘Newton’), Плиний, Долгоруков, Гринич (norm. Гринвич), Гвадалквивир, Термопилы, аглинский (norm английский English), едемский (norm эдемский), афинский.
2.	The second   class is the diachronic part, which includes three items.

Diachronic

Obsolete words

Non-standard variants

Morphologic archaisms 

Spelling variants 

Morphologic variants

Phonetic variants 

2.1	The first group includes off-lexicon word-forms which are mostly obsolete words and their derivatives. Variation of prefixes and suffixes is included here.
E.g.: Тако (norm. так ‘so’), егда (когда ‘if, when’), магазейн (norm. магазин ‘shop’), зрети (church-slavonic ‘to see’), наблюдательство (norm. наблюдение ‘supervision’), неможно (norm. нельзя ‘it’s impossible’).
2.2	The second group consists of non-standard variants of the words which belong to the corpus lexicon. The types of these non-standard variants are as follows. 
•	Spelling variants are the most numerous, including variation in word splitting (written as a single word or as several separated words). 
E.g.: полаты (norm. палаты ‘palace’), толко (norm. только ‘only’), протчих (norm. прочих ‘other’), зделать (norm. сделать ‘to do’), гдеб (norm. где б ‘wherever’), коммисия (norm. комиссия ‘comission’), явятца (norm. явятся ‘to appear’).
•	Phonetic variants represent out-of-date pronunciation of different words, and, first of all, loanwords.
E.g.: гарнадер and гранодер (norm. гренадер ‘grenadier’), сараценах (norm. сарацинах ‘Saracen’), гистория (norm. история ‘history’), ирои (norm. герои ‘heroes’), есквадра (norm. эскадра ‘squadron’).
•	Morphologic variants are rather numerous (more than 17% of the whole number of variants). They are word-forms which do not correspond to the standard language (but may be generally used in contemporary colloquial languages and dialects).
E.g.: егерОВ (norm. егерЕЙ), клянуСЯ, боялиСЯ (norm. клянуСЬ, боялиСЬ), произвесТЬ (norm. произвесТИ), вытаращА, воспользуЯСЬ (norm. вытаращИВ, воспользОВАВШИСЬ), по стУ (norm. по стО).
2.3. The third group of the diachronic part of the lexicon includes morphologic archaisms. This is a term for morphologic forms which belonged to the previous states of the grammar system and have been conserved in idioms, proverbs, and citations in the modern language (на босу ногу, на круги своя, темна вода во облацех). In the 18th century texts old forms were used more widely. Among them are:
Infinitive forms with -ти ending (восприяТИ, зреТИ and so on, instead of восприяТЬ, зреТЬ), Nom-Acc plural with -Ы ending (городЫ, домЫ instead of городА, дома), 
Dat plural детЕМ, людЕМ, крестьянОМ instead of детЯМ, людЯМ, крестьянАМ.
It is a problem for the tagger to identify such forms, so it suggests improbable hypotheses about their grammar features.

4. Using the information retrieved from the lexical database of the Corpus

How are we supposed to deal with this information retrieved from the lexical database of the Corpus? 
Firstly, new significant proper names and out-of-date words with their derivatives should be introduced to the corpus lexicon.
Secondly, historical variants of different kind should be included in corresponding lemmas in the corpus lexicon. This enables the parser to recognize words and analyze them correctly irrespective of different variants of spelling and inflexion. For instance, lemma офицер would contain the variant афицер, lemma амбар would contain the variant анбар, non-standard forms боятися, боялися, боюся, бояся would be added to the list of the word-forms of the verb бояться.
Thirdly, we have to derive the list of archaic morphologic forms, supply them with grammatical meanings and add them to the tagger lexicon. Including the information about old grammatical variants to the lexicon enables us to avoid of a great amount of incorrect analyses. For example, in the case of Church Slavonic forms of Present 2 p sg with –ши ending 16 verbs give more than 160 incorrect hypotheses. See below the analysis of the verb form Praes, 2p, sg отягощаеши ‘weight down’
отягощаеши отягощаесать 2p,act,bastard,imper,pf,sg,v 1
отягощаеши отягощаесывать 2p,act,bastard,imper,pf,sg,v 1
отягощаеши отягощаехать 2p,act,bastard,imper,pf,sg,v 1
отягощаеши отягощаеш bastard,inan,m,nom,pl,s 1
отягощаеши отягощаеш acc,bastard,inan,m,pl,s 1
отягощаеши отягощаеша anim,bastard,f,nom,persn,pl,s 1
отягощаеши отягощаеша anim,bastard,f,gen,persn,s,sg 1
отягощаеши отягощаеша anim,bastard,m,nom,persn,pl,s 1
отягощаеши отягощаеша bastard,f,gen,inan,s,sg 1
отягощаеши отягощаеша acc,bastard,f,inan,pl,s 1
отягощаеши отягощаешать 2p,act,bastard,imper,pf,sg,v 1
отягощаеши отягощаешивать 2p,act,bastard,imper,pf,sg,v 1,
etc. - total 23 false analyses

The idea of the tagger lexicon supplemented with units described above may be regarded as a module for tagging texts of the diachronic corpus. Moreover, it may be useful for analyzing texts of religious and historical subject area in the modern language corpora.
We intend to use the so called ‘shuttle’ method. The corpus lexicon compiled from the ‘pilot’ corpus of 3 millions words is supposed to be used for annotating new texts. Thereby higher levels of accuracy in automatic annotation are expected to be achieved. Then the whole corpus should be retagged, and the results of annotation, especially the new list of bastards, should be analyzed again. Then the new supplement to the lexicon should be prepared, and so on.

Conclusions

The results of the work in progress are relevant for both theoretical and applied researches.
1) The full observation of the 18th century language hasn’t ever been conducted with such representative material. We are hoping to solve some of the topical problems of the literary language studies. How is the 18th century language state different from the contemporary language qualitatively and quantitatively? How has the language system developed from archaic to contemporary in different language spheres? Will corpus researches allow us to specify the periodization of the literary language history?
2) The practical aim is to compile an electronic dictionary, which would be used for morphologic analysis. This would significantly upgrade the quality of the automatic annotation.
3) Vocabulary database which is analyzed for the purpose of the corpus optimization may be used in lexicography for compiling electronic and printed dictionaries – historical dictionaries of variants, dictionaries of rare words – and also for writing grammar reference books.

References

Baron, A., P. Rayson (2009) “Automatic standardization of texts containing spelling variations: How much training data do you need?” In Abstracts of Corpus Linguistics 2009, July 20-23, University of Liverpool, UK
Bennet, P., M. Durrel, S. Scheible, R.J.Whitt (2009) “Annotating a multigenre corpus of Early Modern German” In Abstracts of Corpus Linguistics 2009, July 20-23, University of Liverpool, UK
Davies, M. (2007) “Competing demands of size, speed, and annotation with historical corpora” (2007) In Dagstuhl Seminar Proceedings 06491 Digital Historical Corpora – Architecture, Annotation, and Retrieval. Available at: http://drops.dagstuhl.de/opus/volltexte/2007/1056
Ernst-Gerlach, A. (2007) “Retrieval in text collections with historic spelling” (2007) In Dagstuhl Seminar Proceedings 06491 Digital Historical Corpora – Architecture, Annotation, and Retrieval. Available at: http://drops.dagstuhl.de/opus/volltexte/2007/1056
Hauser, A., M. Heller, E. Leiss, K.U. Shulz, C. Wanzeck (2007) “Information Access to Historical Documents from the Early New High German Period” In Dagstuhl Seminar Proceedings 06491 Digital Historical Corpora – Architecture, Annotation, and Retrieval. Available at: http://drops.dagstuhl.de/opus/volltexte/2007/1057
Meyer, R. (2009) “Semi-automatic morphosyntactic tagging of a diachronic corpus of Russian” In Abstracts of Corpus Linguistics 2009, July 20-23, University of Liverpool, UK
Pilz, T. (2007) “Searching in text databases with non-standard orthography” In Dagstuhl Seminar Proceedings 06491 Digital Historical Corpora – Architecture, Annotation, and Retrieval. Available at: http://drops.dagstuhl.de/opus/volltexte/2007/1053
Rayson, P., D. Archer, A. Baron, J. Culpeper and N. Smith (2007a) “Tagging the Bard: Evaluating the accuracy of a modern POS tagger on Early Modern English Corpora” In Proceedings of Corpus Linguistics 2007, July 27-30, University of Birmingham, UK
Rayson, P., D. Archer, A, Baron, N. Smith (2007b) “Tagging historical corpora – the problem of spelling variation” In Dagstuhl Seminar Proceedings 06491 Digital Historical Corpora – Architecture, Annotation, and Retrieval. Available at: http://drops.dagstuhl.de/opus/volltexte/2007/1055
Russian National Corpus. Available at: http://ruscorpora.ru/en/corpora-morph.html; http://ruscorpora.ru/en/corpora-sem.html
Savchuk, S., D. Sichinava, I. Garipov (2006). Podkorpus tekstov XVIII veka v sostave Natsionalnogo kopusa russkogo jazyka: iz opyta raboty. In Web Journal on Formal, Computational and Cognitive Linguistics. Available at: http://fccl.ksu.ru/issue_spec /docs/Savchuk_Sichinava_Garipov.doc
Savchuk, S. (2007) “Corpus-based Investigation of Language Change: the Case of RNC” In Proceedings of the Corpus Linguistics 2007 July 27-30, University of Birmingham, UK Available at http://ucrel.lancs.ac.uk/publications/CL2007/final/181/181_Paper.pdf
Savchuk, S., E. Grishina (2008). Variation in Russian. Dictionary Project. In: Computational Linguistics and Intellectual Technologies. Papers from the Annual International Conference “Dialogue” Issue 7 (14). M: RGGU
Savchuk, S., D. Sichinava (2009) “Korpus russkih tekstov XVIII veka v sostave Natsionalnogo kopusa russkogo jazyka: problemy i perspektivy” In Natsionalnyi korpus russkogo jazyka: 2006-2008 (forthcoming) 
Savchuk, S. (2009) “Korpus tekstov pervoy poloviny XX veka: tekuscheje sostojanije i perspektivy” In Natsionalnyi korpus russkogo jazyka: 2006-2008 (forthcoming) 
Vinogradov, V. V. (1978) Osnovnye etapy istorii russkogo jazyka,  in V.V. Vinogradov. Izbrannye trudy. Istorija russkogo literaturnogo jazyka, pp. 10-64. Moscow: Nauka.
Zaliznyak, A. (1977; 2004) Grammaticheskij slovar’ russkogo jazyka. M: Russkije slovari