B. Irsyad Putra, Frenki, and Kartika S, “Implementation of the Surtax on Non-Metallic Mineral and Rock Taxes in Bandar Lampung City: An Analysis of Siyāsah Tanfīdhiyyah on Mayor Regulation Number 1 of 2025”, Al-Risalah, pp. 1280–1294, May 2026.