Pommaret, J. F., <br/><br/>
Systems of partial differential equations and Lie pseudogroups 
by J. F. Pommaret ; with a pref. by Andre Lichnerowicz. 
 - New York  Gordon and Breach Science Publishers  1978. 
 - xiv, 411 pages :   illustration, ;    24 cm. 
 - Mathematics and its applications (Gordon and Breach Science Publishers) ; v.14. .
<br/><br/> Includes index. 
<br/><br/>Bibliography: p. 405-407. 
<br/><br/><label>ISBN: </label>067700270X 
<br/><br/><label>Subjects--Topical Terms: </label><br/>Differential equations, Partial<br/>Lie groups<br/>Pseudogroups