A. G. Nikitin, “Group classification of systems of nonlinear reaction-diffusion equations with triangular diffusion matrix”, Ukr. Mat. Zhurn., vol. 59, no. 3, pp. 395–411, Mar. 2007, Accessed: Dec. 05, 2025. [Online]. Available: https://umj.imath.kiev.ua/index.php/umj/article/view/3315