Gaya APA
Internasional, T, R, G.
(1989).
Encyclopedia Americana: Annual 1989
.
Danbury:
Grolier Incorporated.
Gaya MLA
Internasional, Tim, Redaksi, Grolier.
"Encyclopedia Americana: Annual 1989".
Danbury:
Grolier Incorporated,
1989.
Text.