Yahya, A., and I. Maesaroh. “Standard Operational Procedures for Congregational Services During The Covid-19 Pandemic at The Head Office Of Shafira Tour Travel Surabaya.”. Proceedings of International Conference on Da’wa and Communication, Vol. 3, no. 1, Nov. 2021, pp. 336-44, https://proceedings.uinsa.ac.id/index.php/ICONDAC/article/view/666.