It wasnarrated from Salim that his father said:
"The Messenger ofAllah(ﷺ) used to pray two Rak'ah while traveling, and he did not domore than that. And he used to pray Tahajjud at night." I asked:"Didhe pray Witr?" He said: "Yes." (RU)
English reference (RU): Vol. 1, Book 5, Hadith 1193 (RU)
Arabic reference (RU): Book 5, Hadith 1249 (RU)