K. Gallo, R. T. Bratfalean, A. C. Peacock, N. G. Broderick, C. B. Gawith, L. Ming, P. G. Smith, and D. J. Richardson, "Quadratic interactions in an hexagonally poled lithium niobate buried waveguide,"
in Nonlinear Guided Waves and Their Applications, A. Sawchuk, ed.,
Vol. 80 of OSA Trends in Optics and Photonics
(Optical Society of America, 2002), paper NLWC5.