BHATTACHARYYA, P., D. K. RAKSHIT, and A. C. DE. “Line Type Angel Echoes Observed at Dum Dum Airport, Calcutta”. MAUSAM 16, no. 2 (April 1, 1965): 249–254. Accessed January 20, 2025. https://mausamjournal.imd.gov.in/index.php/MAUSAM/article/view/5638.