Citazione Stile APA (7a Edizione)
(1990). Year Book. The 1990 World Book: A Review of the Events of 1989.The Annual Supplement to The World Book Encyclopedia. The World Book,Inc.
Citazione stile Chigago Style (17a edizione)
Year Book. The 1990 World Book: A Review of the Events of 1989.The Annual Supplement to The World Book Encyclopedia. Chicago: The World Book,Inc, 1990.
Citatione MLA (9a ed.)
Year Book. The 1990 World Book: A Review of the Events of 1989.The Annual Supplement to The World Book Encyclopedia. The World Book,Inc, 1990.
Attenzione: Queste citazioni potrebbero non essere precise al 100%.