AVULA, Xavier J.R. <br/><br/>
Mathematical modelling : An intenational journal - v 1 no 4 

 - New York  pergamon press  1981 
 - 271-411p. 
<br/><br/><label>ISBN: </label>0 80 026487 5 
<br/><br/><label>Dewey Class. No.: </label>511.8