Godoy, T., and M. Urciuolo. “About the $L^p$-Boundedness of Integral Operators With Kernels of the Form $K_1(x-y)K_2(x+y)$”. MATHEMATICA SCANDINAVICA, vol. 78, June 1996, pp. 84-92, doi:10.7146/math.scand.a-12575.