The implementation of the integral routines is based on the formulation in Refs. . For the sake of brevity, no attempt is made here to summarize the intricate derivations of all the different subcases. However, we noticed a small mistake in the case for k = 2 j + 1 and sj < 0 (case 2, subcase 2), which has been corrected only recently in an erratum . Since the argument is rather subtle, the problem will be explained below at some length.