APA
United Nations Children´s Fund (UNICEF), direct, .The state of the world´s children 1990. Estados Unidos: Oxford University Press.
Chicago
United Nations Children´s Fund (UNICEF), direct, .The state of the world´s children 1990. Estados Unidos: Oxford University Press.
Harvard
United Nations Children´s Fund (UNICEF), direct, .The state of the world´s children 1990. Estados Unidos: Oxford University Press.
MLA
United Nations Children´s Fund (UNICEF), direct, .Estados Unidos: Oxford University Press. .