Precalculus 
by      Aufmann, Richard N.; Barker, Vernon C.; Nation, Richard 
 - Boston,USA.  Houghton Mifflin Company  1991 
 - v-ix  617p 
<br/><br/><label>ISBN: </label>0395570514 
<br/><br/><label>LC Class. No.: </label>512.1