1. M. S. Agranovich, “Mixed problems in a Lipschitz domain for strongly elliptic second-order systems,” Funkts. Analiz i Ego Prilozh., 45, No. 2, 1–22 (2011).
2. M. S. Agranovich, Sobolev Spaces, Their Generalizations and Elliptic Problems in Domains with Smooth and Lipschitz Boundaries [in Russian], MTsNMO, Moscow (2013).
3. V. G. Babskii, N. D. Kopachevsky, A. D. Myshkis, L. A. Slobozhanin, and A. D. Tyuptsov, Zero Gravity Hydromechanics [in Russian], Nauka, Moscow (1976).
4. Yu. M. Berezanskii, Expansion in Eigenfunctions of Self-Adjoint Operators [in Russian], Naukova Dumka, Kiev (1965).
5. O. V. Besov, V. P. Il’in, and S. M. Nikol’skii, Integral Representations of Functions and Embedding Theorems [in Russian], Nauka, Moscow (1975).