S P Tampubolon and D S Palupi 2025. THEORETICAL STUDY OF STOCHASTIC DIFFERENTIAL EQUATIONS AND PROBABILITY DENSITY FUNCTION FOR LINEAR AND NONLINEAR GEOMETRIC BROWNIAN MOTION: KAJIAN TEORITIK PERSAMAAN DIFERENSIAL STOKASTIK DAN PROBABILITY DENSITY FUNCTION BAGI GERAK BROWNIAN GEOMETRIK LINEAR DAN NONLINEAR. PROSIDING SEMINAR NASIONAL FISIKA (E-JOURNAL). 13, 1 (Jan. 2025), FA–250.