1. Aleksandrov, P.S., Efremovich, V.A.: The Basic Concepts of Topology: an Outline. Moscow Leningrad: ONTI 1936, 94 pp.
2. Hilbert, D., Cohn-Vossen, S.: Anschauliche Geometrie. Berlin: Springer 1932, 310 pp. Zbl. 5, 112
3. Boltyanskij, V.G., Efremovich, V.A.: Descriptive Topology. Moscow: Kvant, No. 21, 1982, 149 pp. [German transl.: Braunschweig 1986]. Zbl. 606. 57001
4. Chinn, W.G., Steenrod, N.: First Concepts of Topology. New York: Random House 1966, 115 pp. Zbl. 172, 242
5. Volovik, G.B., Mineev, V.P.: Physics and Topology. Moscow: Znanie 1980, 63 pp. Mineev, V.P.: Topological Objects in Nematic Liquid Crystals. Addendum to the