Alya Zulfa Cahyani, Elvina, Agus Rahmat Hermawanto, and Novrihan Leily Nasution, “Analysis Price and Promotion of Customer Loyalty in Modern Retail Shopping Centers in The Pandemic Time Covid-19 Through The Purchase Decision Strategy as Moderation ”, IJBTOB, vol. 1, no. 1, pp. 35–46, Feb. 2021.