Isnaini, B. et al. 2026. Exploring Spatial Nonstationarity in the Number of Motor Vehicles in East Java Using Robust Geographically Weighted Regression with an MM-Estimator. PYTHAGORAS Jurnal Matematika dan Pendidikan Matematika. 20, 2 (Jan. 2026). DOI:https://doi.org/10.21831/pythagoras.v20i2.90866.