Gaya APA
Oven, A, V.
(1981).
Gratia commercil
.
Zwolle:
W.E.J. Tjeenk Willink.
Gaya MLA
Oven, A., Van.
"Gratia commercil".
Zwolle:
W.E.J. Tjeenk Willink,
1981.
Buku.