S. A. Al-Zanganee, “Conversion to a Greener Fleet A Cost-Benefit Analysis of a Conversion to Compressed Natural Gas for a Municipal Bus Fleet”, IJSSES, vol. 1, no. 2, pp. 25–34, Dec. 2014, Accessed: Apr. 21, 2026. [Online]. Available: https://www.ijsses.tiu.edu.iq/index.php/ijsses/article/view/494