P. Sathishmohan, V. Rajendran, C. Vignesh Kumar, and P.K. Dhanasekaran. “On Nano Semi Pre Neighbourhoods in Nano Topological Spaces”. Malaya Journal of Matematik 6, no. 01 (January 1, 2018): 294–298. Accessed July 16, 2024. https://www.malayajournal.org/index.php/mjm/article/view/811.