Free-Riding Behavior in Vaccination Decisions: An Experimental Study Ibuka, Yoko ; Li, Meng ; Vietri, Jeffrey ; Chapman, Gretchen B. ; Galvani, Alison P. Abstract Publication: PLoS ONE Pub Date: January 2014 DOI: 10.1371/journal.pone.0087164 Bibcode: 2014PLoSO...987164I