Mahmood, T., and A. Ejaz. “On Bipolar Valued Fuzzy 𝒌-Ideals in Hemirings”. The Nucleus 52, no. 3 (August 7, 2015): 115–122. Accessed June 16, 2024. http://www.thenucleuspak.org.pk/index.php/Nucleus/article/view/644.