Bogaevski, V. N. <br/><br/>
Algebraic methods in nonlinear pertubation theory   
by V.N.Bogaevski, A.Povzner 
 - New York  Springer-Verlag  1991 
 - xii, 265p. 
 - Applied Mathematical Sciences  V.88 .
<br/><br/><label>ISBN: </label>0387974911 
<br/><br/><label>Dewey Class. No.: </label>515.35  / N911