Sudev, N.K., and K.A. Germina. “A Study on Integer Additive Set-Valuations of Signed Graphs”. Carpathian Mathematical Publications 7, no. 2 (December 15, 2015): 236–246. Accessed May 6, 2024. https://journals.pnu.edu.ua/index.php/cmp/article/view/1403.