1.
Vassilev V. GROUP PROPERTIES OF A CLASS OF FOURTH-ORDER PARTIAL DIFFERENTIAL EQUATIONS. Ann. Sofia Univ. Fac. Math. and Inf. [Internet]. 1991 Dec. 12 [cited 2024 Nov. 24];82(2):163-78. Available from: https://ftl5.uni-sofia.bg./index.php/fmi/article/view/542