Sunan Ibn Majah, Volume 2, Book 5, Hadith 1193 (DarusSalam) ⓘ
It was narrated from Salim that his father said: “The Messenger of Allah used to pray two Rak’ah while traveling, and he did not do more than that. And he used to pray Tahajjud at night.” I asked: “Did he pray Witr?” He said: “Yes.”
حَدَّثَنَا أَحْمَدُ بْنُ سِنَانٍ، وَإِسْحَاقُ بْنُ مَنْصُورٍ، قَالاَ حَدَّثَنَا يَزِيدُ بْنُ هَارُونَ، أَنْبَأَنَا شُعْبَةُ، عَنْ جَابِرٍ، عَنْ سَالِمٍ، عَنْ أَبِيهِ، قَالَ كَانَ رَسُولُ اللَّهِ ـ صلى الله عليه وسلم ـ يُصَلِّي فِي السَّفَرِ رَكْعَتَيْنِ لاَ يَزِيدُ عَلَيْهِمَا وَكَانَ يَتَهَجَّدُ مِنَ اللَّيْلِ . قُلْتُ وَكَانَ يُوتِرُ قَالَ نَعَمْ .
also referenced under: Hadith 1193 (Reference) & Book 5, Hadith 1249 (In-Book)