APA (7th ed.) Citation

Gale Group. (2011). Countries of the world and their leaders yearbook 2012. Gale.

Chicago Style (17th ed.) Citation

Gale Group. Countries of the World and Their Leaders Yearbook 2012. Detroit, Mich: Gale, 2011.

MLA (8th ed.) Citation

Gale Group. Countries of the World and Their Leaders Yearbook 2012. Gale, 2011.

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