%0 Journal Article %A W. Mlak %T An example of the equation $u_t = u_{xx} + f(x, t, u)$ with distinct maximum and minimum solutions of a mixed problem %J Annales Polonici Mathematici %D 1963 %P 101-103 %V 13 %N 1 %I mathdoc %U http://geodesic.mathdoc.fr/articles/10.4064/ap-13-1-101-103/ %R 10.4064/ap-13-1-101-103 %G en %F 10_4064_ap_13_1_101_103