Porter, Patricia A.  1939- <br/><br/>
Active English / 
Patricia A. Porter, Allen W. Sharp 
 - Englewood Cliffs, N.J. :  Prentice-Hall,  1977 
 - v. :  ill. ;  28 cm. 
<br/><br/> Book 3, book 1 : understand, practice, communicate 
<br/><br/><label>ISBN: </label>0130034002 
<br/><br/><label>LCCN: </label>76-56230 
<br/><br/><label>Subjects--Topical Terms: </label><br/>English language--Textbooks for foreigners