Solitons in two-dimensional arrays of χ(2) Waveguides - Malomed, B. A.; Kevrekidis, P. G.; Frantzeskakis, DJ; Nistazakis, H.E.; Yannacopoulos, A.N. (Pacific Rim Conference on Lasers and Electro-Optics, CLEO - Technical Digest, 2002)