BMJ. 1999 May 08;318(7193):1280-3. doi: 10.1136/bmj.318.7193.1280.
BMJ (Clinical research ed.)
J A Spencer, R K Jordan
PMID: 10231266 PMCID: PMC1115656 DOI: 10.1136/bmj.318.7193.1280
[No abstract available.]