Gaya APA
Mines., B, O. (1975).
Mineral Facts & Problems, Bulletin 667,1975 Edition .
United States of America:
The bureau of foreign relation.
Gaya MLA
Mines., Bureau, Of.
"Mineral Facts & Problems, Bulletin 667,1975 Edition".
United States of America:
The bureau of foreign relation,
1975.
Text.