Fadilah, A., A. Fitrianto, and I. Sumertajaya. “OUTLIER IDENTIFICATION ON PENALIZED SPLINE REGRESSION MODELING FOR POVERTY GAP INDEX IN JAVA”. BAREKENG: Jurnal Ilmu Matematika Dan Terapan, Vol. 16, no. 4, Dec. 2022, pp. 1231-40, doi:10.30598/barekengvol16iss4pp1231-1240.