Fadol, H. T. A. “Study the Possibility of Address Complex Models in Linear and Non-Linear Causal Relationships Between Oil Price and GDP in KSA: Using the Combination of Toda-Yamamoto, Diks-Panchenko and VAR Approach”. International Journal of Energy Economics and Policy, vol. 10, no. 6, Oct. 2020, pp. 672-8, https://www.econjournals.com/index.php/ijeep/article/view/10130.