M. D. Nafis, N. Asnawi, and V. M. Ekowati, “Cryptocurrency Zakat in the Perspective of Fiqh Wāqi‘iyyah: Takyīf Fiqhī and Legal Implications for Bitcoin and Tether (USDT)”, bamj, vol. 4, no. 3, pp. 521–531, Nov. 2026.