Anton V. Zimmerling. A tale of two auxiliaries: third person forms of byti in Old Russian
RJANO. 2022. № 2 (44), Pages. 9 - 84

Anton V. Zimmerling. Do they deserve it? ― Are endoclitics necessary for the description of Russian?
RJANO. 2018. № 2 (36), Pages. 159 - 179

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