Sihombing, Denny Jean Cross. “Elementary School Communication Transformation: Developing a Parent-Teacher Communication and Information System With the Spiral Method”. Jurnal Info Sains : Informatika dan Sains 13, no. 03 (December 1, 2023): 777–784. Accessed April 21, 2026. https://ejournal.seaninstitute.or.id/index.php/InfoSains/article/view/3385.