Abu Maysarah narrates: A man came to Sayyiduna Abdullah bin Mas'ud (may Allah be pleased with him) and said: O Abu Abd al-Rahman! May witr be prayed after the adhan? He said: "Yes, and after the iqamah as well."
Hadith Referenceالمعجم الكبير للطبراني / باب العين / 9384