ARTICLE Mader_DGOV_2026/IDIAP You Are How You Pay: Understanding and Identifying the Payment Behavior of Socio-Demographic Groups Mader, Aurel Ruben Jüttner, Matthias Gatica-Perez, Daniel ACM Digital Government: Research and Practice 7 2 2026 https://dl.acm.org/doi/10.1145/3797478 URL