Oberschall, Anthony, Opportunities and framing in the Eastern European revolts of 1989 , In McAdam, Doug ; McCarthy, John D.; Zald, Mayer N., Comparative Perspectives on Social Movements: Political Opportunities, Mobilizing Structures, and Cultural Framings Cambridge, Cambridge University Press, , 1996, pp. 93-121 Emphasises the importance of the nonviolent moral force versus a force that had the means of control and repression but lacked moral authority.