Sunan an-Nasa'i, Volume 2, Book 13, Hadith 1291 (DarusSalam) ⓘ
It was narrated from Musa bin Talha that: His father said: "We said: 'O Messenger of Allah, how should we send salah upon you?' He said: 'Say: Alahumma salli 'ala Muhammad wa 'ala ali Muhammad, kama sallaita 'ala Ibrahima wa barik 'ala Muhammad kama barakta 'ala ali Ibrahim fil-'alamin, innaka hamidun majid (O Allah, send salah upon Muhammad and upon the family of Muhammad, as You sent salah upon the family of Ibrahim, and send blessings upon Muhammad and upon the family of Muhammad as You sent blessings upon the family of Ibrahim among the nations. You are indeed Worthy of praise, Full of glory.)'"
أَخْبَرَنَا إِسْحَاقُ بْنُ إِبْرَاهِيمَ، قَالَ أَنْبَأَنَا مُحَمَّدُ بْنُ بِشْرٍ، قَالَ حَدَّثَنَا مُجَمِّعُ بْنُ يَحْيَى، عَنْ عُثْمَانَ بْنِ مَوْهَبٍ، عَنْ مُوسَى بْنِ طَلْحَةَ، عَنْ أَبِيهِ، قَالَ قُلْنَا يَا رَسُولَ اللَّهِ كَيْفَ الصَّلاَةُ عَلَيْكَ قَالَ " قُولُوا اللَّهُمَّ صَلِّ عَلَى مُحَمَّدٍ وَعَلَى آلِ مُحَمَّدٍ كَمَا صَلَّيْتَ عَلَى إِبْرَاهِيمَ وَآلِ إِبْرَاهِيمَ إِنَّكَ حَمِيدٌ مَجِيدٌ وَبَارِكْ عَلَى مُحَمَّدٍ وَعَلَى آلِ مُحَمَّدٍ كَمَا بَارَكْتَ عَلَى إِبْرَاهِيمَ وَآلِ إِبْرَاهِيمَ إِنَّكَ حَمِيدٌ مَجِيدٌ " .
also referenced under: Hadith 1290 (Reference) & Book 13, Hadith 112 (In-Book)