Purwadi, Ari, Suhandi Suhandi, and Umi Enggarsasi. 2019. “Urban Air Pollution Control Caused by Exhaust Gas Emissions in Developing Country Cities in Public Policy Law Perspective”. International Journal of Energy Economics and Policy 10 (1):31-36. https://www.econjournals.com/index.php/ijeep/article/view/8337.