Cita APA (7th ed.)
Porterfield, J. D., & St. Pierre, R. W. (1992). Healthful aging. Dushkin Pub. Group.
Cita Chicago (17th ed.)
Porterfield, James D., i Richard W. St. Pierre. Healthful Aging. Guilford, CT: Dushkin Pub. Group, 1992.
Cita MLA (9th ed.)
Porterfield, James D., i Richard W. St. Pierre. Healthful Aging. Dushkin Pub. Group, 1992.
Atenció: Aquestes cites poden no estar 100% correctes.