This chapter is based in part on
Abramowitz and Stegun (1964, Chapter 16), by L. M. Milne-Thomson.
The main references used in writing this chapter are
Whittaker and Watson (1927), Lawden (1989), and
Walker (1996). For further bibliographic reading see
McKean and Moll (1999) and Armitage and Eberlein (2006).