Cita APA (7a ed.)

(1981). 1981: Britannica book of the year. Encyclopaedia Britannica.

Cita Chicago Style (17a ed.)

1981: Britannica Book of the Year. Chicago: Encyclopaedia Britannica, 1981.

Cita MLA (8a ed.)

1981: Britannica Book of the Year. Encyclopaedia Britannica, 1981.