Sakti, Baiq Yani Permata, et al. “The Role of Self-Efficacy and Optimism on Academic Stress Towards Industrial Engineering Students at Universitas Ahmad Dahlan, Yogyakarta Batch 2017-2019”. International Journal of Sciences: Basic and Applied Research (IJSBAR), vol. 53, no. 1, July 2020, pp. 35-42, https://gssrr.org/JournalOfBasicAndApplied/article/view/11443.