Idris, Ismail Tijjani, and Sabri Nayan. 2017. “A PMG Approach to the Joint Effects of Oil Price Changes and Environmental Risks on Non-Performing Loans: Evidence from Organisation of the Petroleum Exporting the Countries”. International Journal of Energy Economics and Policy 7 (3):345-51. https://econjournals.com./index.php/ijeep/article/view/5072.