1) Islamic Awareness https://www.islamic-awareness.org/quran/text/mss/ 2) The History of The Quranic Text The History of The Quranic Text, from Revelation to Compilation - 2nd Edition: A Comparative Study with the Old and New Testaments - Muhammad Mustafa Al-Azami 3) Hunting for the word of God Hunting for the Original Word of God: the quest for the original text of the New Testament and the Qur'an in light of textual and historical criticism - Sami Ameri 4) The Ahruf/Modes of recitation Variant readings of the Quran - Ahmad 'Ali Al-Imam