Collagen but not fibrinogen surfaces induce bleb formation, exposure of phosphatidylserine and procoagulant activity of adherent platelets: evidence for regulation by tyrosine kinase-dependent Ca2+ responses. - Heemskerk, JWM; Vuist, WMJ; Feijge, MAH; Reutelingsperger, CPM; Lindhout, T (Blood, 1997)