00349nam a2200121Ia 4500082002000000100002300020245004700043260003500090300002100125500005400146500000500200700002200205  a515.35bOv96.GA  aOvsiannikov, L. V.  aGroup analysis of differential equationsb  aNew YorkbAcademic Pressc1982  axvi, 416p. Index  a"Translation from the Russian ed. by W. F. Ames".  a  aAmes, W. F. ; ed.