@article{DE_1994_30_3_a11, author = {M. B. Sheftel}, title = {Group analysis of defining equations~-- a method for finding recursion operators}, journal = {Differencialʹnye uravneni\^a}, pages = {444--456}, publisher = {mathdoc}, volume = {30}, number = {3}, year = {1994}, language = {ru}, url = {http://geodesic.mathdoc.fr/item/DE_1994_30_3_a11/} }