Maria N. Sheveleva. East Slavic imperfective verbs with the suffix -yva -/-iva - and the literary tradition
Trudy IRY RAS. 2016. № 3 (9), Pages. 208 - 223

Maria N. Sheveleva. ON THE HISTORY OF THE OLD RUSSIAN VERB byvati (Aspectual Semantics)
Trudy IRY RAS. 2016. № 4 (10), Pages. 526 - 543