International Energy Agency. (2021). Spot market and crude oil import costs: Crude oil import costs and index (Edition 2021). OECD Publishing. https://doi.org/10.1787/fc588cba-en
Chicago-Zitierstil (17. Ausg.)International Energy Agency. Spot Market and Crude Oil Import Costs: Crude Oil Import Costs and Index (Edition 2021). Paris: OECD Publishing, 2021. https://doi.org/10.1787/fc588cba-en.
MLA-Zitierstil (9. Ausg.)International Energy Agency. Spot Market and Crude Oil Import Costs: Crude Oil Import Costs and Index (Edition 2021). OECD Publishing, 2021. https://doi.org/10.1787/fc588cba-en.
Achtung: Diese Zitate sind unter Umständen nicht zu 100% korrekt.