On a Linear Partial Differential Equation of the Higher Order in Two Variables with Initial Condition Whose Coefficients are Real-valued Simple Step Functions. J. Part. Diff. Eq. [Internet]. 2016 Mar. 5 [cited 2025 Dec. 5];29(1):1-13. Available from: https://www.global-sci.com/index.php/jpde/article/view/14961