Gaya APA
Scientific Event Alert Network (SEAN) Bulletin Volume 14, No. 12, Desember 31, 1989. ().
Washington:
Smithsonian Istitution.
Gaya MLA
Scientific Event Alert Network (SEAN) Bulletin Volume 14, No. 12, Desember 31, 1989.
.
Washington:
Smithsonian Istitution,
.
.