1. Ansari QH, Sharma PK (2019) Ekeland type variational principle for set-valued maps in quasi-metric spaces with applications. J Nonlinear Convex Anal 20(8):1683–1700
2. Ansari QH, Sharma PK (2021a) Set order relations, set optimization, and ekeland’s variational principle, in optimization, variational analysis and applications. In: Laha V, Maréchal P, Mishra SK (eds) Springer Proceedings in Mathematics and Statistics, vol 355. Springer Nature Singapore Pvt. Ltd., pp 103–165
3. Ansari QH, Sharma PK (2021b) Levitin-Polyak well-posedness for set optimization problems. J Nonlinear Convex Anal 22(7):1353–1371
4. Ansari QH, Sharma PK, Yao JC (2018) Minimal element theorems and Ekeland’s variational principle with new set order relations. J Nonlinear Convex Anal 19:1127–1139
5. Ansari QH, Hamel AH, Sharma PK (2020) Ekeland’s variational principle with weighted set order relations. Math Methods Oper Res 91:117–136