Taddaga, Tsafitri Rinti, and Abdul Muhid. “The Effectiveness of Psychological Capital Training to Improve the Optimism Attitude in Mandiri Enterprises: Literature Review”. Jurnal Ekonomi, Bisnis & Entrepreneurship, vol. 16, no. 1, Apr. 2022, pp. 50–59, https://doi.org/10.55208/dknmhw86.