Изместьев А.А. Contractions of Lie algebras and separation of variables. From two-dimensional hyperboloid to pseudo-euclidean plane / А.А.Изместьев,Г.С.Погосян, 1998. - 12 p. - Текст : непосредственный.
Lie algebra contractions for overlap functions / A.A.Izmest'ev,G.S.Pogosyan,A.N.Sissakian и др., 1999. - 16 с. - Текст : непосредственный.
Contractions of Lie algebras and separation of variables. The n-dimensional sphere / A.A.Izmest'ev,G.S.Pogosyan,A.N.Sissakian,P.Winternitz, 1998. - 36 p. - Текст : непосредственный.
Contractions of lie algebras and separation of variables / A.A.Izmest'ev,G.S.Pogosyan,A.N.Sissakian,P.Winternitz, 1996. - 15 p. - Текст : непосредственный.