Because PCFs are special cases of confluent hypergeometric functions, the methods of computation described in §13.29 are applicable to PCFs. These include the use of power-series expansions, recursion, integral representations, differential equations, asymptotic expansions, and expansions in series of Bessel functions. See, especially, Temme (2000) and Gil et al. (2004c, 2006a, 2006b, 2011a, 2011b).