Porter, R.L. <br/><br/>
Further elementary analysis 

 - LoNew Delhion  Bell & Hyman  1982 
 - xi, 368p., 22 cm. 
<br/><br/><label>ISBN: </label>0713515945 
<br/><br/><label>Dewey Class. No.: </label>515,  / DD, Por