1. V. V. Fedorchuk and V. V. Filippov, General Topology. Basic Constructions [in Russian], Moscow State university, Moscow (1988).
2. A. V. Arkhangel'skii and V. I. Ponomarev, Elements of General Topology in Problems and Exercises [in Russian], Nauka, Moscow (1974).
3. R. Engel'king, General Topology [Russian translation], Mir, Moscow (1986) (see R. Engelking, Outline of General Topology, North-Holland (1968)).