Prolonged thromboprophylaxis following hip replacement surgery-results of a double-blind, prospective, randomised, placebo- controlled study with dalteparin - Dahl, OE; Andreassen, G; Aspelin, T; Muller, C; Mathiesen, P; Nyhus, S; Abdelnoor, M; Solhaug, JH; Arnesen, H (Thromb Haemost, 1997)