Cita APA

Encyclopedia Britannica, Inc. (1991). Britannica Book of the year 1991. Encyclopedia Britannica.

Citación estilo Chicago

Encyclopedia Britannica, Inc. Britannica Book of the Year 1991. Chicago: Encyclopedia Britannica, 1991.

Cita MLA

Encyclopedia Britannica, Inc. Britannica Book of the Year 1991. Encyclopedia Britannica, 1991.

Warning: These citations may not always be 100% accurate.