Webb, Eugene, J. <br/><br/>
Unobtrusive measures 
/ Eugene, J. Webb...[et.al 
 - Ccalif  Sage publication  2000 
 - xix, 220 p.- 
 - Sage classics, 2 .
<br/><br/><label>ISBN: </label>761920110 
<br/><br/><label>Subjects--Topical Terms: </label><br/>Social science
<br/><br/><label>Dewey Class. No.: </label>300.72  / UNO