Opanasenko, S. “Equivalence Groupoid of a Class of General Burgers-Korteweg-De Vries Equations With Space-Dependent Coefficients”. Transactions of Institute of Mathematics, the NAS of Ukraine, vol. 16, no. 1, Sept. 2019, pp. 131-54, https://trim.imath.kiev.ua/index.php/trim/article/view/371.