︠I︡Ulian Markhlevskiĭ o sovetsko-polʹskikh otnosheni︠i︡akh v 1918-1921 gg - Chernykh, M. N. (Akademi︠i︡a nauk SSSR, In-t slav︠i︡anovedeni︠i︡a i balkanistiki, 1990)