Jurgaitis, Donatas, and Arvydas-Juozapgs Janavičius. “Reduction of System of Partial Derivatives With Nilpotent Matrix”. Lietuvos matematikos rinkinys 40, no. spec. (December 18, 2000): 132–135. Accessed April 26, 2025. https://journals.vu.lt./LMR/article/view/35077.