Abstract. There are several errors in [SIAM J. Math. Anal., 9, 1, (1978), pp. 76–86]. In particular, the kernel form for the integral representation of the product for two Jacobi functions of the second kind in (2.10) has an incorrect lower-bound of integration and an incorrect multiplicative factor of [Formula: see text]. There are also several typographical errors in the Nicholson-type formula for Jacobi functions and Laguerre functions in the trigonometric context. In this erratum we explain what these errors are and how they should be fixed.