1.
Apakov YP, Dzhuraev TD. On the theory of the third-order equation with multiple characteristics containing the second time derivative. Ukr. Mat. Zhurn. [Internet]. 2010Jan.25 [cited 2024May5];62(1):40 -51. Available from: https://umj.imath.kiev.ua/index.php/umj/article/view/2842