1. Y. Luke, Mathematical Functions and Their Approximations (Academic Press, New York, 1975; Mir, Moscow, 1980).
2. H. Bateman and A. Erdélyi, Higher Transcendental Functions, Vol. 1: The Hypergeometric Function, Legendre Functions (McGraw-Hill, New York-Toronto-London, 1953; Nauka, Moscow, 1965 and 1973 (2nd ed.)).
3. C. L. Siegel, “Über einige Anwendungen diophantischer Approximationen,” Abhandlungen Akad. Berlin, No. 1 (1929).
4. C. L. Siegel, Transcendental Numbers, in Ann. of Math. Stud. (Princeton Univ. Press, Princeton, NJ, 1949), Vol. 16.
5. A. B. Shidlovskii, Transcendental Numbers (Nauka, Moscow, 1987) [in Russian].