Jagadesan, S., and M. V. Subramanian. “Study on Sunspots, Ozone and Earth Atmosphere Variation at Pudukkottai, Tamilnadu (latitude: 10 0 23’ and Longitude 78 0 52’)”. International Journal of Science and Engineering Invention 2, no. 08 (September 25, 2016): 205 to 212. Accessed April 3, 2025. http://ijsei.in/index.php/ijsei/article/view/34.