Cita APA (7a ed.)
(1989). <The> 1989 World Book Year Book: <The> Annual Supplement to The World Book Encyclopedia (1. ed.). World Book.
Cita Chicago Style (17a ed.)
<The> 1989 World Book Year Book: <The> Annual Supplement to The World Book Encyclopedia. 1. ed. Chicago: World Book, 1989.
Cita MLA (9a ed.)
<The> 1989 World Book Year Book: <The> Annual Supplement to The World Book Encyclopedia. 1. ed. World Book, 1989.
Precaución: Estas citas no son 100% exactas.