(a) Sayyiduna Anas bin Malik (may Allah be pleased with him) says that the Messenger of Allah (peace and blessings be upon him), Abu Bakr, Umar and Uthman (may Allah be pleased with them) (the narrator says: I think he also named the fourth, Ali (may Allah be pleased with him)) all recited qunut until I parted from them.
(b) In the narration of Abd al-Warith bin Sa'id the morning prayer is mentioned. For these hadiths there are supporting reports (shawahid) from the Prophet (peace and blessings be upon him) and from his Caliphs.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الصلاة / 3106