The following are some articles by Mark Davies (creator of COHA), which serve as good introductions to the corpus:

  • (2012) “Expanding Horizons in Historical Linguistics with the 400 million word Corpus of Historical American English”. Corpora 7: 121-57.

  • (2012) "Examining Recent Changes in English: Some Methodological Issues". In The Oxford Handbook of the History of English, eds. Terttu Nevalainen and Elizabeth Closs Traugott. Oxford: Oxford Univ. Press. 263-87.

Also (for related historical corpora from English-Corpora.org):

  • (2019) If olive oil is made of olives, then what’s baby oil made of? The shifting semantics of Noun+Noun sequences in American English. In J. Egbert & P. Baker (Eds.), Using corpus methods to triangulate linguistic analysis, New York: Routledge. 163-84. (With Jesse Egbert)

  • (2019) Historical shifts with the into-causative construction in American English. Linguistics 57: 29-58. (With Jong-Bok Kim)

  • (2018) Using (and useful) corpora for the study of the history of English. In Teaching the History of the English Language, eds. Chris Palmer and Colette Moore. MLA Options for Teaching Series.

  • (2016) The Effect of Representativeness and Size in Historical Corpora: An Empirical Study of Changes in Lexical Frequency. In Studies in the History of the English Language VII: Generalizing vs. particularizing methodologies in historical linguistic analysis, eds. Don Chapman, Colette Moore, and Miranda Wilcox. Berlin: De Gruyter / Mouton. 131-50. (With Don Chapman)

  • (2014) Making Google Books n-grams useful for a wide range of research on language change”. International Journal of Corpus Linguistics 19 (3): 401-16. (BYU Google Books corpus)

  • (2012) Recent shifts with three nonfinite verbal complements in English: Data from the 100 million word TIME Corpus (1920s-2000s)". In Current Change in the English Verb Phrase, ed. Bas Aarts, et al. Cambridge: Cambridge Univ. Press. 46-67. (TIME Corpus)

  • (2011) The Corpus of Contemporary American English as the First Reliable Monitor Corpus of English". Literary and Linguistic Computing 25: 447-65. (COCA and very recent change)