Widyaningsih, Heni, et al. , translators. “The Effect of Engagement in Digital Health Challenges and Gamification Features of Applications on Increasing Physical Activity Among Millennials in Jakarta”. West Science Social and Humanities Studies , vol. 3, no. 09, Sept. 2025, pp. 1254-66, https://doi.org/10.58812/wsshs.v3i09.2227.