L A Lyusternik

THE SOLUTION OF SOME PERTURBATION PROBLEMS FOR MATRICES AND SELFADJOINT OR NON-SELFADJOINT DIFFERENTIAL EQUATIONS I

M. Vishik, L. Lyusternik, M I Vishik, 1960 .

New Work in the Probabilistic Theory of Special Functions

L. Lyusternik, L A Lyusternik, 1978 .