@misc{RahmanShaikhAlietal., author = {Rahman, Md Sadikur and Shaikh, Ali Akbar and Ali, Irfan and Bhunia, Asoke Kumar and F{\"u}genschuh, Armin}, title = {A Theoretical Framework for Optimality Conditions of Nonlinear Type-2 Interval-Valued Unconstrained and Constrained Optimization Problems Using Type-2 Interval Order Relations}, series = {Mathematics}, volume = {9}, journal = {Mathematics}, number = {8}, issn = {2227-7390}, doi = {10.3390/math9080908}, language = {en} }