1. Dunaev, V.V. and Polyakov, O.M. (1987), “Methodological aspects of relational classification theory”, NTI, ser. 2, no. 4, pp. 21–27.
2. Moore, E. (1910), “Introduction to a form of general analysis”, AMS Colloquium Publishing, Yale Univ. Press, New Haven, USA.
3. Birkhoff, G. (1984), Teoriya reshetok [Lattice Theory], Transl. by Salii, V.N., Nauka, Moscow, Russia.
4. Polyakov, O. M. (1986), “Klassifikatsionnaya model’ dannykh”, NTI, ser. 2, pp. 13–20.
5. Kuratowski, K. (1966), Topologiya [Topology], Transl. by Antonovskii, M.Ya., vol. 1, Mir, Moscow, Russia.