1. H. Bateman and A. Erdelyi, Higher Transcendental Functions, I: The Hypergeometric Function, Legendre Functions, McGraw—Hill, New York—Toronto—London, 1953; Russian translation: Nauka, Moscow, 1965.
2. S. A. Zlobin, Uspekhi Mat. Nauk [Russian Math. Surveys], 57 (2002), no. 3, 153–154.