PSI :  personalized system of instruction 41 Germinal papers. 

 - Reading,MA. :  W. A. Benjamin,Inc.,  c1974. 
 - 225 p. 
<br/><br/><label>Subjects--Topical Terms: </label><br/>Independent Study.
<br/><br/><label>LC Class. No.: </label>LB1049  / .S485