APA Style
OPEC bulletin Vol. 4 2019. (2019).
Vienna, Austria:
Opec.
Chicago Style
OPEC bulletin Vol. 4 2019.
.
Vienna, Austria:
Opec,
2019.
Buletin.
MLA Style
OPEC bulletin Vol. 4 2019.
.
Vienna, Austria:
Opec,
2019.
Buletin.
Turabian Style
OPEC bulletin Vol. 4 2019.
Vienna, Austria:
Opec,
2019.
Buletin.