Johnson, David W. <br/><br/>
The new circles of learning  coperation in the classroom and school 
Dawid W. Johnson - Roger T. Johnson - Edythe Johnson Holubec 
 - Washington :  Association for Supervision and Curriculum Development,  1994 
 - 111 p. :  ill. ;  23 cm. 
<br/><br/>p. 106-110 
<br/><br/><label>ISBN: </label>0871202271 
<br/><br/><label>Subjects--Topical Terms: </label><br/>Group work in education<br/>Cooperation--Study and teaching