Hakobyan, G.S., and Siavash Ghorbanian. “INITIAL-BOUNDARY VALUE PROBLEM FOR SECOND ORDER DEGENERATE PSEUDOHYPERBOLIC EQUATIONS”. Proceedings of the YSU A: Physical and Mathematical Sciences, vol. 46, no. 2 (228), May 2012, pp. 10-13, doi:10.46991/PYSU:A/2012.46.2.010.