Wlodarczyk, A., N. Basabe, D. Páez, and L. Zumeta. “Hope and Anger As Mediators Between Collective Action Frames and Participation in Collective Mobilization: The Case of 15-M”. Journal of Social and Political Psychology, Vol. 5, no. 1, May 2017, pp. 200-23, doi:10.5964/jspp.v5i1.471.