Samoilenko, A. M., V. G. Samoilenko, and Yu. M. Sidorenko. 1999. “Hierarchy of the Kadomtsev-Petviashvili Equations under Nonlocal Constraints: Many-Dimensional Generalizations and Exact Solutions of Reduced System”. Ukrains’kyi Matematychnyi Zhurnal 51 (1), 78–97. https://umj.imath.kiev.ua/index.php/umj/article/view/4585.