Dementiev , S.N. and Yanovsky , L.P. (1992) “Solubility of the nonlinear Valle Pussen problems ”, Ukrains’kyi Matematychnyi Zhurnal, 44(5), pp. 700–703. Available at: https://umj.imath.kiev.ua/index.php/umj/article/view/7968 (Accessed: 7 April 2025).