Musnad Abu Ya'la al-Mawsili 115:37

Hadb ibn Khalid narrated to us, Hammam narrated to us, Qatadah narrated to us, he said: We said to Anas, "Who collected the Quran during the time of the Messenger of Allah, may Allah bless him and grant him peace?" He said, "Four, all of them from the Ansar: Ubayy ibn Ka'b, Mu'adh ibn Jabal, Zayd ibn Thabit, and a man from the Ansar who is called Abu Zayd."