Al-Matalib al-'Aliyah 637 — Witr

It is narrated from Imam al-Hakam (may Allah have mercy on him) that he said to Miqsam (may Allah have mercy on him): "I pray three rak'ahs of witr, then the adhan is called and I go out (for the prayer)." He said: "This (practice) is not correct except with five or seven rak'ahs (of witr)." Imam al-Hakam (may Allah have mercy on him) relates: I informed Imam Mujahid and Yahya bin al-Jazzar (may Allah have mercy on them both) of this, and the two of them said to me: "Ask him on whose authority this is." So he replied: "This narration is reported from the most trustworthy and reliable persons, Sayyidah Aishah and Sayyidah Maymunah (may Allah be pleased with them both)."
And Imam Abu Bakr (may Allah have mercy on him) said: Ghundar narrated this same narration to us through Shu'bah; however, it does not mention his going back to Imam Mujahid and Yahya.