Musannaf Ibn Abi Shayba 3:3390

5767. 'Abd al-A'la narrated to us, from al-Jurayri, from Khalid al-Ahdab, from his uncle Safwan ibn Muhriz, who said: The prayer of Safwan on the day of al-Fitr and al-Nahr was ten rak'ahs before the exit of the Imam, and two rak'ahs after the Imam.