Não informado. (1953). Occupational health bulletin. Department of National Health and Welfare, Industrial Health Division.
Citação do estilo Chicago (17ª ed.)Não informado. Occupational Health Bulletin. Ottawa: Department of National Health and Welfare, Industrial Health Division, 1953.
Citação MLA (8ª ed.)Não informado. Occupational Health Bulletin. Department of National Health and Welfare, Industrial Health Division, 1953.
Rhybudd: Mae'n bosib nad yw'r dyfyniadau hyn bob amser yn 100% cywir.