1. [Er] A. Erdélyi (Ed.). Higher Transcendental Functions. Vol. 1. McGraw-Hill, 1953.
2. [GRS] I. M. Gelfand, V. S. Retakh and V. V. Serganova. Generalized Airy functions, Schubert cells, and Jordan groups. Dokl. Akad. Nauk SSSR 298(1988), 17-21
3. Engl. transl. in Sov. Math. Dokl. 37 (1988), 8-12.
4. [Ho] J. Hörn. Hypergeometrische Funktionen zweier Veranderlichen. Math. Ann. 105 (1931), 381-407; 111 (1935), 638-677; 113 (1937), 242-291.
5. [Hu] P. Humbert. Sur les fonctions hypercylindriques. C.R. Acad. Sci. Paris 171 (1920), 490-492.