1. St John of God Hospital, Geelong, Box 1087, Victoria 3220, Australia.
2. Sendai National Hospital, Miyagino 2-8-8, Miyagino-Ku, Miyagi 983-8520, Japan.
3. Cumbria Farm, 9362 McCain Road, Shreveport, Louisiana 71107, USA.
4. Nuffield Orthopaedic Centre, Windmill Road, Oxford OX3 7LD, UK.