The authors are pleased to acknowledge the assistance of
B. L. J. Braaksma with §§16.5 and 16.11.
The main references used in writing this chapter are Erdélyi et al. (1953a),
Luke (1969a, 1975). For additional bibliographic reading see
Appell and Kampé de Fériet (1926), Andrews et al. (1999) and Slater (1966).