I'm writing about Personal Task Management systems (PTMs) like Habitica for class. If you have any scholarly, professional, or just plain fun sources about the users, development, or features of PTMs please share them in a comment :D
Azfar, A., Choo, K. R., & Liu, L. (2017). Forensic taxonomy of android productivity apps. Multimedia Tools and Applications, 76(3), 3313-3341. DOI 10.1007/s11042-016-3718-2
Bellotti, V., Dalal, B., Good, N., Flynn, P., Bobrow, D. G., & Ducheneaut, N. (2004). What a to-do: Studies of task management towards the design of a personal task list manager.
Haraty, M., McGrenere, J., & Tang, C. (2015). How and why personal task management behaviors change over time. Graphics Interface Conference 2015.
Jolaoso, S. & Perez-Quinones, M. A. (2015). TaskAmbient: A study in personal task management visualization. 33rd Annual ACM Conference, 1797-1802. doi:10.1145/2702613.2732890
Kamsin, A. (2014). Improving tool support for personal task management (PTM) (Doctoral dissertation). ACM Digital Library. DOI: 10.1145/2212776.2212457
Zibetti, E., Chevalier, A., & Eyraud, R. (2012). What type of information displayed on digital scheduling software facilitates reflective planning tasks for students? Contributions to the design of a school task management system. Computers in Human Behavior, 28, 591-607. doi:10.1016/j.chb.2011.11.005