Piaget, Jean,  1896-1980 <br/><br/>
Six psychological studies / 
Jean Piaget ; tr., introd., notes and glossary David Elkind. 
 - New York :  Vintage,  1968. 
 - 169 p. 
<br/><br/><label>Encabezamiento--Tema: </label><br/>Niņo, Estudio del