Partial differential equations 
Yu. V. Egorov, M. A. Shubin (eds.). 
 - Berlin  Springer-Verlag  1991. 
 - vol. ;  24 cm. 
 - Encyclopaedia of mathematical sciences  v.33. .
<br/><br/> Title of the Russian version : Differentsial'nye uravneniya chastnymi proizvodynymi. 
<br/><br/>p. 227-235 
<br/><br/><label>ISBN: </label>354053363X 
<br/><br/><label>Subjects--Topical Terms: </label><br/>Mathematical analysis<br/>Differential equations, Hyperbolic