Collagen but not fibrinogen surfaces induce bleb formation, exposure of phosphatidylserine, and procoagulant activity of adherent platelets: evidence for regulation by protein tyrosine kinase-dependent Ca2+ responses - Heemskerk, J W; Vuist, W M; Feijge, M A; Reutelingsperger, C P; Lindhout, T (Blood, 1997)