Beczek, Jan. “Solutions of a Nonlinear Dirichlet Problem in Which the Nonlinear Part Is Bounded from above and below by Polynomials”. Mathematical Modelling and Analysis 2, no. 1 (December 15, 1997): 35-40. Accessed November 1, 2024. https://gc.vgtu.lt/index.php/MMA/article/view/10007.