Sunan An-Nasai, Chapter: The Book of the Times (of Prayer)

that his father was in the Masjid of Amr bin Shurahbil and the Iqamah for prayer was said, so they were waiting for him. He said: "I was praying Witr, and Abdullah was asked: 'Is there any Witr after the Adhan?' He said: "Yes, and after the Iqamah, and he narrated that the Prophet (saw) slept and missed the prayer until the sun arose then prayed.'" And the wording is that of Yahya. (Sahih)