Encyclopaedia Britannica, i. (1997). Medical and health annual 1998. Encyclopaedia Britannica.
Cita Chicago (17th ed.)Encyclopaedia Britannica, inc. Medical and Health Annual 1998. Chicago: Encyclopaedia Britannica, 1997.
Cita MLA (9th ed.)Encyclopaedia Britannica, inc. Medical and Health Annual 1998. Encyclopaedia Britannica, 1997.
Atenció: Aquestes cites poden no estar 100% correctes.