Hafiz, M., and D. Tanjung. “Penetapan Kalender Hijriah Menurut Ulama Muhammadiyah Dan Nahdatul Ulama Di Indonesia”. JURNAL EDUKASI NONFORMAL, Vol. 3, no. 2, Sept. 2022, pp. 357-66, https://jurnal.unimen.cloud/JENFOL/article/view/5041.