The main source of Jonas Jablonskis’ Lietuviškos kalbos gramatika (Grammar of the Lithuanian language, Tilsit, 1901 [JaG]), signed under the pseudonym of Petras Kriaušaitis, is Petras Avižonis’ Liėtuviška Gramatikėlė (Small Lithuanian Grammar, [Petersburg, 1898] [AvG]). However, Jablonskis significantly supplemented AvG by adding the chapters on preposition, conjunction, interjection, syntax and orthography. He also separated the descriptions of noun and adjective, added chapters on phonetics, pronoun, numeral, verb, used Lithuanian language terms. Jablonskis did not indicate other sources in JaG, fragments of the text taken from other works are not identified as such. However, later Jablonskis wrote that he also used Kazimieras Jaunius’ Li...