Olajide, Johnson Taiwo, Jubril Oluwatoyin Fantola, and Olufemi Aderemi Ayansola. “Measuring Economic Growth in OPEC Countries : A Panel Data Approach”. International Journal of Applied Mathematical Research 4, no. 2 (April 30, 2015): 345–350. Accessed April 28, 2024. https://www.sciencepubco.com/index.php/ijamr/article/view/4544.