Sari, Syifa, and Wendi Usino. 2018. “UPAYA PENINGKATAN PELAYANAN DAN LOYALITAS CUSTOMER PERJALANAN WISATA DI PT. ELHASBU MULIA UTAMA”. IDEALIS : InDonEsiA JournaL Information System 1 (3), 94-101. https://jom.fti.budiluhur.ac.id/index.php/IDEALIS/article/view/103.