A Cross-Country European Efficiency Measurement of Maritime Transport: A Data Envelopment Analysis Approach. - Phi-Hung Nguyen; Thi-Ly Nguyen; Thi-Giang Nguyen; Duc-Thinh Nguyen; Thi-Hoai Tran; Hong-Cham Le; Huong-Thuy Phung (Axioms, 2022)