Irina S. Yuryeva. Conditional conjunctions in the original Old Russian texts of different genres
RJANO. 2022. № 2 (44), Pages. 85 - 124

M. Lazar. Evidential Particle de(i) and Other Evidential Particles in the History of Russian
RJANO. 2011. № 2 (22), Pages. 116 - 138