What Does It Take? Developing a Smartphone App that Motivates Older Adults to be Physically Active. - Sabrina Haque; Kyle Henry; Troyee Saha; Kimberly Vanhoose; Jobaidul Boni; Samantha Moss; Kate Hyun; Kathy Siepker; Xiangli Gu; Angela Liegey-Dougall; Stephen Mattingly; Christoph Csallner (CoRR, 2025)