Yahya related to me from Malik from Abdullah ibn Abi Bakr ibnHazim from his father that Amr ibn Sulaym az-Zuraqi said, "Abu Humaydas-Saidi told me that they asked the Messenger of Allah, may Allahbless him and grant him peace, how they were to ask for blessings uponhim and he replied that they should say, 'O Allah, bless Muhammad andhis wives and his descendants asYou blessed the family of Ibrahim, andgive baraka to Muhammad and his wives and his descendants as You gavebaraka to the family of Ibrahim. You are worthy of Praise andGlorious.'"Allahumma salli ala Muhammad wa azwajihi wa alihikama sallaita ala ali Ibrahim, wa barakaala Muhammad wa azwajihi waalihi kama baraktaalaali Ibrahim, innaka Hamidu'm - Majid.
USC-MSA web (English) reference: Book 9, Hadith 69
Arabic reference: Book 9, Hadith 400