Widhigdo JC, Ahuluheluw JM, Pandjaitan LN. The hardiness training to improve psychological well-being of the members of student organization at Universitas Surabaya. JPU [Internet]. 2020 Jun. 16 [cited 2024 Dec. 16];7(2):122-39. Available from: https://publication.k-pin.org/index.php/jpu/article/view/104