Cook, A. B. S., and S. Yucel. “Soundness of the Heart: An Analysis of the Unique Qualities of the Qalb Salīm”. Teosofi: Jurnal Tasawuf Dan Pemikiran Islam, vol. 12, no. 1, June 2022, pp. 1-21, doi:10.15642/teosofi.2022.12.1.1-21.