Musnad Ahmad 25:1368

Abdullah ibn al-Walid narrated to us, Sufyan narrated to us, from Ibn Jurayj, from al-Hasan ibn Muslim, from Tawus, from Ibn Abbas, who said: "The Messenger of Allah (ﷺ) prayed, then he delivered a sermon, as did Abu Bakr, Umar, and Uthman, on the day of Eid without an Adhan or an Iqamah."