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