Gustafson, Karl E. <br/><br/>
Numerical range; the field of values of linear operators and matrices  / 

 - New York:  Springer-Verlag,  1997 
 - xiv, 189p. Bibl. Index. 
 - Universitext .
<br/><br/><label>ISBN: </label>038794835X 
<br/><br/><label>Dewey Class. No.: </label>515.72  / G982.NR