Singularities in linear wave propagation 
Gårding, Lars, 
 - Berlin ; | New York :  Springer-Verlag,   vol. 2." 
 - 123 p. :  ill. ;  25 cm. 
 - P.R. China .
<br/><br/> Subseries: Nankai Institute of Mathematics 
<br/><br/><label>ISBN: </label>354018001X (Berlin) | 038718001X (New York)