Universidad de Aconcagua – Sistema de Bibliotecas:
<br/>
<br/>Focus groups :  theory and practice / 
David W. Stewart, Prem N. Shamdasani. 
 - Newbury Park, Calif. :  Sage Publications,  1990. 
 - 153 p. :  ill. ;  23 cm. 
 - Applied social research methods series ;  v. 20 .