Alexei A. Gippius, Dmitri V. Sitchinava. Addenda et corrigenda for previously published birchbark letters [XIII]: a pre-publication
RJANO. 2021. № 2 (42), Pages. 178 - 259

Dmitri V. Sitchinava. Re-reading pluperfect: a new overview of the examples of pluperfect in birchbark letters
RJANO. 2020. № 1 (39), Pages. 136 - 171