Byanju, R. M., M. B. Gewali, and K. Manandhar. “Low Cost Passive Monitoring of Nitrogen Dioxide and Sulphur Dioxide in Ambient Air”. Journal of Nepal Chemical Society 27, no. 1 (July 16, 2012): 34–45. Accessed July 25, 2024. https://www.nepjol.info/index.php/JNCS/article/view/6439.