KholyavkaO. T. “Hyperbolic Variational Inequality of the Third Order With Variable Exponent of Nonlinearity”. Ukrains’kyi Matematychnyi Zhurnal 66, no. 4 (April 25, 2014): 518–530. Accessed December 5, 2020. http://umj.imath.kiev.ua/index.php/umj/article/view/2154.