Research Article Authors of the world, unite. . . Br Med J (Clin Res Ed) 1982; 284 doi: https://doi.org/10.1136/bmj.284.6331.1726 (Published 12 June 1982) Cite this as: Br Med J (Clin Res Ed) 1982;284:1726 Article Related content Metrics Responses Peer review This is a PDF-only article. The first page of the PDF of this article appears below.