Encyclopaedia Britannica, i. (1997). Medical and health annual 1998. Encyclopaedia Britannica.
Cita Chicago Style (17a ed.)Encyclopaedia Britannica, inc. Medical and Health Annual 1998. Chicago: Encyclopaedia Britannica, 1997.
Cita MLA (9a ed.)Encyclopaedia Britannica, inc. Medical and Health Annual 1998. Encyclopaedia Britannica, 1997.
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