Source:
International journal of epidemiology [Int J Epidemiol] 1974 Dec; Vol. 3 (4), pp. 287-94.Publisher: Oxford University Press Country of Publication: England NLM ID: 7802871 Publication Model: Print Cited Medium: Print ISSN: 0300-5771
Source:
British medical journal [Br Med J] 1974 Apr 20; Vol. 2 (5911), pp. 133.Publisher: British Medical Association Country of Publication: England NLM ID: 0372673 Publication Model: Print Cited Medium: Print ISSN: