Kotzev J.N. Permutational magnetic point groups and their application in the Landau theory of phase transitions. General theory and chromomorphic classification / J.N.Kotzev,S.S.Tzonev, 1990. - 15 p. - Текст : непосредственный.
Kotzev J.N. Permutational magnetic point groups and their application in the Lnadau theory of phase transitions. Transitive permutational representations / J.N.Kotzev,S.S.Tsonev, 1990. - 18 p. - Текст : непосредственный.
Kotzev J.N. Permutational magnetic point groups and their application in the Landau theory of phase transitions. Complete list of tables / J.N.Kotzev,S.S.Tzonev, 1990. - 13 p. - Текст : непосредственный.
Alexandrova D.A. On the problem of the equivalence of P-type permutational colour groups / D.A.Alexandrova,J.N.Kotzev, 1990. - 16 p. - Текст : непосредственный.
Kotzev J.N. A three state potts model with colour group symmetry / J.N.Kotzev,M.K.Peev, 1990. - 16 p. - Текст : непосредственный.