Pennington, Bruce Frankiln,  1946- <br/><br/>
What Piaget's conservation of number task doesn't tell us about a childs understanding of numerical invariance  [ microform] / 
by Bruce Franklin Pennington 
 - Ann Arbor, Mich. :  University Microfilms International,  1977 
 - 1 mirofilm reel :  positive ;  35 mm. 
<br/><br/>Thesis (Ph.D.) - Duke University, 1977 
<br/><br/><label>Subjects--Topical Terms: </label><br/>Number concept<br/>Mathematical ability