Não informado. (1981). ACP observer. American College of Physicians.
Chicagoスタイル(17版)引用形式Não informado. ACP Observer. Philadelphia, Pa: American College of Physicians, 1981.
MLA(8版)引用形式Não informado. ACP Observer. American College of Physicians, 1981.
警告: この引用は必ずしも正確ではありません.