Статья 1910 Hakob Margaryan David Hovhannisyan Nune Hakobyan Tigran Sargsyan Petros Gasparyan David Pokhsraryan Nelson Tabiryan Journal of Nonlinear Optical Physics & Materials Vol.22, No.4 1350042-7 2013 http://www.worldscientific.com/worldscinet/jnopm