BUWANA, R. “MEMBANGUN CUSTOMER RELATIONSHIP MANAGEMENT (CRM) MENGGUNAKAN SMS CENTER BERBASIS SMS GATEWAY MENGGUNAKAN PHP (STUDI KASUS RSI SULTAN AGUNG SEMARANG)”. Information Technology and Telematics, Vol. 6, no. 1, Apr. 2016, https://www.unisbank.ac.id/ojs/index.php/fti3/article/view/3867.