Sayyiduna Ibn Abbas (may Allah be pleased with them both) said: The Noble Prophet (peace and blessings be upon him) used to recite «سَبِّحِاسْمَرَبِّكَالْأَعْلَى», «قُلْيَاأَيُّهَاالْكَافِرُونَ», and «قُلْهُوَاللَّهُأَحَدٌ» in the three rak‘ahs of Witr.
Hadith Referenceسنن دارمي / من كتاب الصللاة / 1625