1. B. M. Levitan, ?A theorem of Titchmarsh and Sears,? Usp. Mat. Nauk,16, No. 4, 175?178 (1961).
2. B. M. Levitan and N. N. Meiman, ?A uniqueness theorem,? Dokl. Akad. Nauk SSSR,81, No. 5, 729?731 (1951).
3. Yu. B. Orochko, ?Uniqueness theorem for self-adjoint extensions of the Schrödinger operator with operator potential,? Dopov Akad. Nauk URSR, No. 11, 1391?1393 (1966).
4. Yu. B. Orochko, ?Operator cosine method in the problem of essential self-adjointness of a nonsemibounded symmetric operator,? Ukr. Mat. Zh.,33, No. 3, 348?355 (1981).
5. E. B. Vul, ?Uniqueness theorems for a class of integral representations,? Dokl. Akad. Nauk SSSR,129, No. 4, 722?725 (1959).