(2001). Levels and trends of contraceptive use as assessed in 1998. United Nations.
Citazione stile Chigago Style (17a edizione)Levels and Trends of Contraceptive Use as Assessed in 1998. New York: United Nations, 2001.
Citatione MLA (9a ed.)Levels and Trends of Contraceptive Use as Assessed in 1998. United Nations, 2001.
Attenzione: Queste citazioni potrebbero non essere precise al 100%.