- Dr C F Ryan, Division of Respiratory Medicine, Vancouver General Hospital, 2775 Heather Street, Vancouver, British Columbia, V5Z 3J5 Canada email:
- Received November 22, 1999
- Revision requested January 12, 2000
- Revised February 8, 2000
- Accepted February 8, 2000
- First published May 1, 2000.
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