W. . Ramadhan Harahap, R. . Handayani, Krisna, E. Tri Hartati Harahap, E. . Wardani Hutapea, and M. . Indah Siregar, “Pilgrim Satisfaction and the Effectiveness of Religious Tourism Services: Evidence from Umrah Operations”, J-MD, vol. 6, no. 1, pp. 13–26, Jun. 2025.