Sihombing, D. J. C. “Optimizing Apartment Management through Extreme Programming-Based CRM Application”. Jurnal Info Sains : Informatika Dan Sains, vol. 13, no. 03, Nov. 2023, pp. 744-53, https://ejournal.seaninstitute.or.id/index.php/InfoSains/article/view/3306.