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DOI : 10.1016/0376-0421(75)90010-X

S. Gradshteyn and I. M. Ryshik, Table of Integrals, Series, and Products Academic 14 As noted in 1, there is no singularity in the forward direction. For a more recent discussion within a Born approximation framework, see P. V. Sakov, Akust, 1980.