In Australia the principal investigators were David Barton, M.D., Melbourne, Victoria; Phillip Boyce, M.D., Penrith, New South Wales; Philip L.P. Morris, M.D., Ph.D., Southport, Queensland; and John Tiller, M.D., Melbourne, Victoria. In Canada the principal investigators were Richard Bergeron, M.D., Hull, Quebec; Yves Chaput, M.D., Saint-Jean-Sur-Le-Richelieu, Quebec; Stan P. Kutcher, M.D., Halifax, Nova Scotia; Arumuga Ravindran, M.D., Ottawa, Ontario; and Meir Steiner, M.D., Hamilton, Ontario. In Denmark the principal investigators were Kirsten Behnke, M.D., Frederiksberg; Flemming Bjorndal, M.D., Greve; Peter Ostergaard, M.D., Middelfart; and Jesper A. Sogaard, M.D., Kalundborg. In Norway the principal investigators were Marit Bjartveit-Krüger, M.D., Levanger; Alv A. Dahl, M.D., Oslo; Ingrid Østby-Deglum, M.D., Ottestad; and Torbjørn Sigurdson, M.D., Trondheim. In Sweden the principal investigators were Christer Allgulander, M.D., Huddinge; Goran Björling, M.D., Trollhattan; Anna Loewenstein, M.D., Göteborg; and Ingemar Sjodin, M.D., Linkoping.