Reference

1. https://adepuspita28.wordpress.com/2013/10/26/pengertian-data-flow-diagram-dfd-dan-contoh-gambar-dfd/
2. http://lanuma.web.id/data-flow-diagram-dfd/
3. http://mysoccer88.blogspot.com/2016/06/makalah-apsi-dfd.html
4. http://nita-afrilia.blogspot.com/2011/11/pendekatan-perancangan-sistem.html
5. http://kharismanurhadi.blogspot.com/2012/01/desain-sistem-secara-umum.html
6. https://id.wikipedia.org/wiki/Model_pengembangan_sistem_informasi