(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.
Atenció: Aquestes cites poden no estar 100% correctes.