Reference

Z. A. Efremova (1990): Contributions to the history of investigations o? the fauna and ecology of bumble bees; [Ru; 1 fig., 48 refs. Date: 11.VII.1990]. – In: BLAGOVESHCHENSKAYA, N. N. (ed.) Ecology of Insects and Their Reservation. An Inter-College Collection of Scientific Papers. Ulyanovsk (Ulyanovsk State Pedagogical Institute) – : 44 - 56.