Sahih Bukhari, Chapter: Witr Prayer

I asked Ibn 'Umar, "What is your opinion about the two Rakat before the Fajr (compulsory) prayer, as to prolonging the recitation in them?" He said, "The Prophet (p.b.u.h) used to pray at night two Rakat followed by two and so on, and end the prayer by one Raka Witr. He used to offer two Rakat before the Fajr prayer immediately after the Adhan." (Hammad, the sub-narrator said, "That meant (that he prayed) quickly.)"