Dirk Oegema and Bert Klandermans,
"Why Social Movement Sympathizers Don't Participate: Erosion and
Nonconversion of Support"
American Sociological Review, October 1994, 59: 703-722.
On JSTOR:
http://www.jstor.org/cgi-bin/jstor/viewitem/00031224/di974421/97p0287i/0?config=jstor&frame=noframe&userID=8008b2a9@umd.edu/01cc99332400503f6bf8&dpi=3
