1. N. Akhiezer, The Classical Moment Problem and Some Related Questions in Analysis, Oliver and Boyd, Edinburgh–London, 1965.
2. S. Bernstein, “Sur les polynômes orthogonaux relatifs à un segment fini”, J. de Math., 9 (1930), 127–177; S. Bernstein, J. de Math., 10 (1931), 219–286.
3. M. Sh. Birman and M. Z. Solomyak, “Estimates for the singular numbers of integral operators”, Uspekhi Mat. Nauk, 32:1(193) (1977), 17–84; English transl.: Russian Math. Surveys, 32 (1977), 15–89.
4. M. Sh. Birman, G. E. Karadzhov, and M. Z. Solomyak, “Boundedness conditions and spectrum estimates for the operators $$b(X) a(D)$$ and their analogs”, Adv. Soviet Math., 7 Amer. Math. Soc., Providence, RI, 1991, 85–106.
5. A. Erdélyi, W. Magnus, F. Oberhettinger, and F. G. Tricomi, Higher Transcendental Functions, McGraw-Hill, New York–Toronto–London, 1953.