1. Yu. M. Berezanskii,Expansions in Eigenfunctions of Self-Adjoint Operators [in Russian], Naukova Dumka, Kiev (1965).
2. M. G. Krein, “InfiniteJ-matrices and the matrix moment problem,”Dokl. Akad. Nauk SSSR [Soviet Math. Dokl.],69, No. 3, 125–128 (1949).
3. K. A. Mirzoev, “The Cauchy function andL w p -properties of solutions of quasidifferential equations,”Uspekhi Mat. Nauk [Russian Math. Surveys],46, No. 4 (280), 161–162 (1991).
4. N. I. Akhiezer,The Classical Moment Problem [in Russian], Fizmatlit, Moscow (1961).
5. M. A. Naimark,Linear Differential Operators [in Russian], Nauka, Moscow (1969).