Musannaf Ibn Abi Shayba 21:696

Abu Mu'awiyah narrated to us, from Layth, from Abu al-Zubayr, from Jabir, who said: The Prophet, peace and blessings of Allah be upon him, would not sleep until he recited "Alif Lam Mim, the revelation" (Surah As-Sajdah) and "Blessed is He in whose hand is the dominion" (Surah Al-Mulk).