Gruber, Howard E <br/><br/>
Essential piaget / 
by Howard E Gruber and J Jacques Voneche 
 - London :  Routledge,  1977. 
 - 881p. : 
<br/><br/><label>Subjects--Topical Terms: </label><br/>Piaget
<br/><br/><label>Dewey Class. No.: </label>155.41308  / GRU.E