1. Foothills Medical Centre, 1403
29 St NW, Calgary AB T2N 2T9, Canada.
2. University of Warwick, Clinical
Trials Unit, Coventry, CV4
7AL, UK.
3. Bristol Royal Infirmary, Upper
Maudlin Street, Bristol, BS15NU, UK.
4. Royal Devon and Exeter Hospital, Barrack
Road, Exeter, EX25DW, UK.