LETTERS. - Noonie, Ahilya; Macdonald, Neil; Evans, Barry; Heptonstall, Julia; Channon, K.M.; Cripps, T.R.; Ormerod, O.; Banning, A.P.; Gavery, P.; McGurk, Lynda A.; Fraser, A.G.; Buchalter, Maurice; et al. (BMJ: British Medical Journal (International Edition), 1992)