Akdi, Yilmaz, Serdar Varlik, and Hakan Berument. 2023. “The Long-Run Relationship Between the Prices of WTI and Brent Crude Oils – Periodogram Based Cointegration Analyses”. Energy Economics Letters 10 (1):35-43. https://doi.org/10.55493/5049.v10i1.4715.