Kolosov, Mitrofan Alekseevich (1839 - 1881). Notes on the language and folk poetry in the North-Great Russian dialect. St.Petersburg: printing house of the Imperial Academy of Sciences, 1876 - 1877. : Reports to the Department of the Russian Language and Literature. 1877.
Baudouin de Courtenay, Ivan Alexandrovich (1845-1929). Excerpts from lectures on phonetics and morphology of the Russian language, read in 1880-1881 acad. year in the Emperor. Kazan University. Voronezh: the printing house of the Provincial Government, 1882. Вып. 1. 1882.