1. Li, Dongsheng; Zhang, Kai; An optimal geometric condition on domains for boundary differentiability of solutions of elliptic equations. Journal of Differential Equations 254 (2013), no. 9, 3765–3793.
2. Li, Dongsheng; Zhang, Kai; W^{2,p} interior estimates of fully nonlinear elliptic equations. Bulletin of the London Mathematical Society 47 (2015), no. 2, 301–314.
3. Huang, Yongpan; Li, Dongsheng; Zhang, Kai; Pointwise boundary differentiability of solutions of elliptic equations. Manuscripta Mathematica 151 (2016), no. 3-4, 469–476.
4. Li, Dongsheng; Zhang, Kai; A note on the Harnack inequality for elliptic equations in divergence form. Proceedings of the American Mathematical Society 145 (2017), no. 1, 135–137.
5. Li, Dongsheng; Zhang, Kai; Regularity for Fully Nonlinear Elliptic Equations with Oblique Boundary Conditions. Archive for Rational Mechanics and Analysis 228 (2018), no. 3, 923–967.
6. Lian, Yuanyuan; Zhang, Kai; Boundary pointwise C^{1,α} and C^{2,α} regularity for fully nonlinear elliptic equations. Journal of Differential Equations 269 (2020), no. 2, 1172–1191.
7. Lian, Yuanyuan; Zhang, Kai; Li, Dongsheng; Hong, Guanghao; Boundary Hölder regularity for elliptic equations. Journal de Mathématiques Pures et Appliquées 143 (2020), 311–333.
8. Lian, Yuanyuan; Xu, Wenxiu; Zhang, Kai; Boundary Lipschitz regularity and the Hopf lemma on Reifenberg domains for fully nonlinear elliptic equations. Manuscripta Mathematica 166 (2021), no. 3-4, 343–357.
9. Li, Congming; Zhang, Kai; A note on the Gagliardo-Nirenberg inequality in a bounded domain, Communications on Pure and Applied Analysis, 21 (2022), no. 12, 4013–4017.
10. Wu, Duan; Lian, Yuanyuan; Zhang, Kai; Pointwise Boundary Differentiability for Fully Nonlinear Elliptic Equations, Israel Journal of Mathematics 258 (2023), no. 1, 375–401.
11. Li, Dongsheng; Li, Xuemei; Zhang, Kai; W^{2,p} Estimates for Elliptic Equations on C^{1,α} Domains, Mathematische Annalen 387 (2023), no. 1-2, 57–78.
12. Lian, Yuanyuan; Zhang, Kai*; Boundary pointwise regularity and applications to the regularity of free boundaries, Calculus of Variations and Partial Differential Equations 62 (2023), no. 8, Paper No. 230, 32 pp.
13. Lian, Yuanyuan; Zhang, Kai; A note on the BMO and Calderón-Zygmund estimate, Collectanea Mathematica 75 (2024), no. 1, 1–8.
14. Lian, Yuanyuan; Zhang, Kai; Boundary Lipschitz Regularity and the Hopf Lemma for Fully Nonlinear Elliptic Equations, Potential Analysis 60 (2024), no. 3, 1231–1247.
15. Lian, Yuanyuan; Zhang, Kai; Boundary Hölder Regularity for Elliptic Equations on Reifenberg Flat Domains, Differential and Integral Equations (Accepted), arXiv:1812.11354.