Fushchich W. I. and Zhdanov R. Z. (1992) “Conditional symmetry and reduction of differential equations with partial derivatives ”, Ukrains’kyi Matematychnyi Zhurnal, 44(7), pp. 970-982. Available at: https://umj.imath.kiev.ua/index.php/umj/article/view/8129 (Accessed: 6October2024).