F. Nirmala Irudayam, S.Vinnarasi,. “Pythagorean Vague B-Open Sets Between Pythagorean Vague Topological Spaces”. Mathematical Statistician and Engineering Applications 71, no. 4 (December 30, 2022): 13071–13083. Accessed March 4, 2026. https://www.philstat.org/index.php/MSEA/article/view/2681.