Oksana Yu. Chuikova. The use of genitive partitive with Russian po-verbs: corpus observations
RJANO. 2021. № 1 (41), Pages. 105 - 136

M. V. Gashneva. The Past Imperfect tense in the bylinas of North Russia and the narrative tradition of Old Russian chronicles
RJANO. 2012. № 1 (23), Pages. 179 - 193