Não informado. Public Health Service Publications. U.S. Department of Health Education and Welfare.
Citação do estilo Chicago (17ª ed.)Não informado. Public Health Service Publications. Washington: U.S. Department of Health Education and Welfare.
Citação MLA (8ª ed.)Não informado. Public Health Service Publications. U.S. Department of Health Education and Welfare.
Rhybudd: Mae'n bosib nad yw'r dyfyniadau hyn bob amser yn 100% cywir.