Musonif, A. “The Typology of Authority in Islam (Analysis of the Views of the Islamic Community In Indonesia about Ulil Amri in the Determination of the Beginning of Hijri Months)”. Kontemplasi: Jurnal Ilmu-Ilmu Ushuluddin, Vol. 8, no. 2, Dec. 2020, pp. 253-76, doi:10.21274/kontem.2020.8.2.253-276.