Gilliot et al. 1960–2007. Gilliot, Cl.; Repp, R.C; Nizami, K.A.; Hooker, M.B.; Lin, Chang-Kuan; Hunwick, J.O. (1960–2007). "ʿUlamāʾ". In Bearman, P.; Bianquis, Th.; Bosworth, C.E.; van Donzel, E.; Heinrichs, W.P. (eds.). Encyclopaedia of Islam, Second Edition. doi:10.1163/1573-3912_islam_COM_1278.
On the term uṣūl al-dīn, see Gimaret 1960–2007. On the term 'speculative theology', see, e.g. Schmidtke 2016, p. 2: "rationally minded theologians employed the methods and techniques of speculative theology, ‘kalām’ or ‘ʿilm al-kalām’, as it is typically called". Gimaret, D. (1960–2007). "Uṣūl al-Dīn". In Bearman, P.; Bianquis, Th.; Bosworth, C.E.; van Donzel, E.; Heinrichs, W.P. (eds.). Encyclopaedia of Islam, Second Edition. doi:10.1163/1573-3912_islam_SIM_7760. Schmidtke, Sabine (2016). "Introduction". In Schmidtke, Sabine (ed.). The Oxford Handbook of Islamic Theology. Oxford: Oxford University Press. pp. 1–26. doi:10.1093/oxfordhb/9780199696703.013.48.
