Helmstadter, G. C. <br/><br/>
Research concepts in human behavior :  education, psychology, sociology / 
G. C. Helmstadter. 
 - New York :  Appleton-Century-Crafts,  1970. 
 - 448 p. 
 - The century psychology series .
<br/><br/><label>Encabezamiento--Tema: </label><br/>Ciencias sociales--Investigación