Rai, H.C., Annapurna Sharma, and Vishwa Mohan Sharma. “Studies on Temporal Variation of Acid Precipitation in Delhi”. Asian Journal of Chemistry 21, no. 7 (March 30, 2010): 5391–5398. Accessed July 23, 2024. https://asianpubs.org/index.php/ajchem/article/view/18319.