Platelet aggregation occurs in congenital afibrinogenemia despite the absence of fibrinogen or its fragments in plasma, and platelets, as demonstrated by immunoenzymology - Soria, J; Soria, C; Borg, J V; Mirshashi, M; Pignet, H; Tron, P; Fessard, C; Caen, J P (Br J Haematol, 1985)