APA
POPULATION REFERENCE BUREAU, . (2007). 2007 WORLD POPULATION. WASHINGTON D.C: POPULATION REFERENCE BUREAU.
Chicago
POPULATION REFERENCE BUREAU, . 2007. 2007 WORLD POPULATION. WASHINGTON D.C: POPULATION REFERENCE BUREAU.
Harvard
POPULATION REFERENCE BUREAU, . (2007). 2007 WORLD POPULATION. WASHINGTON D.C: POPULATION REFERENCE BUREAU.
MLA
POPULATION REFERENCE BUREAU, . 2007 WORLD POPULATION. WASHINGTON D.C: POPULATION REFERENCE BUREAU. 2007.
