Cita APA (7th ed.)

(2001). The World almanac and book of facts 2001. World Almanac Books.

Cita Chicago (17th ed.)

The World Almanac and Book of Facts 2001. Mahway, N.J: World Almanac Books, 2001.

Cita MLA (9th ed.)

The World Almanac and Book of Facts 2001. World Almanac Books, 2001.