al-Tasawwuf al-Islami : tarikhuhu wa madarisuhu wa tabi'atuhu wa'athruhu Tasawwuf al-Islami : tarikhuhu wa madarisuhu wa tabi'atuhu wa'athruhu - 'Ayyad, Ahmad Tawfiq (al-Qahirah : Maktabat al-Injilu al-Misriyah, 1970)
Keywords: Sufism; Mysticism -- Islam