1. E. C. Titchmarsh, Eigenfunction Expansions Associated with Second-Order Differential Equations (Claredon, Oxford, 1962; Kom-Kniga, Moscow, 2005).
2. S. Bochner, Lectures on Fourier integrals; with an Author’s Supplement on Monotonic Functions, Stieltjes Integrals, and Harmonic Analysis (Princeton University Press, Princeton, 1959; Fizmatlit, Moscow, 1962).
3. M. M. Dzhrbashyan, Integral Transformation of Functions in Complex Domain (Nauka, Moscow, 1966) [in Russian].
4. A. G. Sveshnikov, A. N. Bogolyubov, and V. V. Kravtsov, Lecture in Mathematical Physics (Nauka, Moscow, 2004) [in Russian].
5. A. I. Zhukov, The Fourier Method in Computational Mathematics (Fizmatlit, Moscow, 1992) [in Russian].