Ellynia E, Tjhin V. Penerapan Customer Relationship Management (CRM) pada Aplikasi Pengiriman Pesan Instan Studi Kasus: WhatsApp, WeChat, Line, KakaoTalk. Ultima InfoSys : Jurnal Ilmu Sistem Informasi [Internet]. 30Jun.2014 [cited 19Apr.2024];5(1):20-6. Available from: https://ejournals.umn.ac.id/index.php/SI/article/view/215