1. Belcheva, R.G. & Bisserov, B.Y. 1982. B-chromosomes in the black rat (Rattus rattus) from Bulgaria. Comptes rendus de l’Académie bulgare des Sciences 35, 1577–1580.
2. Belcheva, R.G. & Kolevska, N.G. 1986. Cytogenetic studies of the common shrew Sorex araneus L. (Soricidae, Insectivora) from the Vitosha Mountain. Comptes rendus de l’Académie bulgare des Sciences 39, 115–118.
3. Belcheva, R.G. & Peshev, D. 1979. Intersubspecific sex chromosome differences in Citellus citellus L. (Rodentia, Sciuridae). Experientia 35, 595–596.
4. Belcheva, R.G. & Peshev, D. 1985. Constitutive heterochromatin in the ground squirrel Citellus citellus L. (Sciuridae, Rodentia) from Bulgaria. Zoologischer Anzeiger 215, 385–390.
5. Belcheva, R.G., Peshev, C.Ch. & Radjabli, S.I. 1977. [Analysis of the chromosome set in the Bulgarian population of Microtus arvalis]. Zoologicheskii zhurnal 56, 315–317(in Russian with English abstract).