Arisandra ML, Kusuma NN. OPTIMIZATION OF SHARIAH-BASED DIGITAL MARKETING STRATEGY TO INCREASE SMARTFREN BRAND LOYALTY THROUGH CUSTOMER ENGAGEMENT ACCORDING TO ISLAMIC ECONOMIC CONCEPT. adilla [Internet]. 2026 Apr. 21 [cited 2026 Jun. 4];9(1):180-203. Available from: https://ejournal.unisda.ac.id/index.php/adilla/article/view/7177