Nguyen TM. EVALUATING THE LEVEL OF FOREIGN LANGUAGE LEARNING INVESTMENT FOR PROFESSIONAL DEVELOPMENT BASED ON DARVIN AND NORTON’S INVESTMENT MODEL IN A VIETNAMESE UNIVERSITY. JFS [Internet]. 2026 Jul. 29 [cited 2026 Aug. 5];42(2S (Special Issue):66-81. Available from: https://jfs.ulis.vnu.edu.vn/index.php/fs/article/view/5692