Gaya APA
LEDGARD, H., Singer, A.
(1982).
Elementary Basic
.
Chicago, America Serikat:
Sciene Reerch Asociates.
Gaya MLA
LEDGARD, Henry., Singer, Andrew.
"Elementary Basic".
Chicago, America Serikat:
Sciene Reerch Asociates,
1982.
Umum.