R. Anandhi, and P. Priya. “A Comparison of Triangular Fuzzy Numbers and Intuitionistic Triangular Fuzzy Numbers Using Apex Base Least Cost Method”. International Journal of Mathematics And Its Applications, vol. 5, no. 4 - F, Dec. 2017, pp. 993-7, https://ijmaa.in/index.php/ijmaa/article/view/1364.