[1] Belgian Red Cross, Ctr Evidence Based Practice, Motstr 42, B-2800 Mechelen, Belgium
[2] Belgian Ctr Evidence Based Med Cebam, Cochrane Belgium, Leuven, Belgium
[3] Univ Ghent, Fac Med & Hlth Sci, Ghent, Belgium
[4] Belgian Red Cross, Blood Serv, Mechelen, Belgium
[5] Katholieke Univ Leuven, Fac Med, Dept Publ Hlth & Primary Care, Leuven, Belgium
[6] Belgian Red Cross, Mechelen, Belgium