An alternative MILP-DEA model to choose efficient unit without explicit inputs. - Guo-Ya Gan; Hsuan-Shih Lee (Ann. Oper. Res., 2019)

Network hierarchical DEA with an application to international shipping industry in Taiwan. - Guo-Ya Gan; Hsuan-Shih Lee; Lynne Lee; Xianmei Wang; Qianfeng Wang (J. Oper. Res. Soc., 2020)

Resolving the infeasibility of the super-efficiency DEA based on DDF. - Guo-Ya Gan; Hsuan-Shih Lee (Ann. Oper. Res., 2021)

Measuring group performance based on metafrontier. - Guo-Ya Gan; Hsuan-Shih Lee (J. Oper. Res. Soc., 2022)