Nguyen, T. M. (2026) “EVALUATING THE LEVEL OF FOREIGN LANGUAGE LEARNING INVESTMENT FOR PROFESSIONAL DEVELOPMENT BASED ON DARVIN AND NORTON’S INVESTMENT MODEL IN A VIETNAMESE UNIVERSITY”, VNU Journal of Foreign Studies, 42(2S (Special Issue), pp. 66–81. doi: 10.63023/2525-2445/jfs.ulis.5692.