Musannaf Ibn Abi Shayba 3:4565

Abu Khalid al-Ahmar narrated to us, from Ash'ath, from al-Hakam, from Ibrahim, who said: Abdullah said: "He does not perform Qunut throughout the whole year in the Fajr prayer, but he performs Qunut in the Witr prayer every night before the bowing (Ruku)." Abu Bakr said: This statement is [the one we hold] according to us.