"Ruth Merttens" <br/><br/>
Abacus Evolve 3: Textbook 1 

 - Oxford  Ginn, Pearson Education Limited  2007 
 - 80 
<br/><br/><label>ISBN: </label>9780602575144 
<br/><br/><label>Dewey Class. No.: </label>510  / 1616