Ferdiana, Ridi, et al. “USER STORY SOFTWARE ESTIMATION:A SIMPLIFICATION OF SOFTWARE ESTIMATION MODEL WITH DISTRIBUTED EXTREME PROGRAMMING ESTIMATION TECHNIQUE”. JUTI: Jurnal Ilmiah Teknologi Informasi, vol. 9, no. 1, Jan. 2011, pp. 41-48, https://doi.org/10.12962/j24068535.v9i1.a67.