Intraoperative measurement of activated partial thromboplastin time and prothrombin time by a portable laser photometer in patients following cardiopulmonary bypass. - Nuttal,G.A.; Oliver,W.C.; Beynen,F.M.; Dull,J.J.; Murray,M.J.; Nichols,W.L. (J Cardiothorac Vasc Anesth, 1993)