Singular pertrubations and asymopotics   
ed. by Richard E.Meyer, Seymour V.Parter 
 - New York  Academic Press  1980 
 - Publication of the Mathematical Research Centre, the University of Wisconsin-Madison  No.45 .
<br/><br/><label>ISBN: </label>0124932606 
<br/><br/><label>Dewey Class. No.: </label>515.35  / N8011