Sunan Abi Dawud 1337

حَدَّثَنَا سُلَيْمَانُ بْنُ دَاوُدَ الْمَهْرِيُّ، حَدَّثَنَا ابْنُ وَهْبٍ، أَخْبَرَنِي ابْنُ أَبِي ذِئْبٍ، وَعَمْرُو بْنُ الْحَارِثِ، وَيُونُسُ بْنُ يَزِيدَ، أَنَّ ابْنَ شِهَابٍ، أَخْبَرَهُمْ بِإِسْنَادِهِ، وَمَعْنَاهُ،، قَالَ ‏:‏ وَيُوتِرُ بِوَاحِدَةٍ، وَيَسْجُدُ سَجْدَةً قَدْرَ مَا يَقْرَأُ أَحَدُكُمْ خَمْسِينَ آيَةً قَبْلَ أَنْ يَرْفَعَ رَأْسَهُ، فَإِذَا سَكَتَ الْمُؤَذِّنُ مِنْ صَلاَةِ الْفَجْرِ وَتَبَيَّنَ لَهُ الْفَجْرُ ‏.‏ وَسَاقَ مَعْنَاهُ ‏.‏ قَالَ ‏:‏ وَبَعْضُهُمْ يَزِيدُ عَلَى بَعْضٍ ‏.‏

This tradition has been transmitted by Ibn Shihab through a different chain of narrators to the same effect. This version adds:He would observe witr with a single rak'ah and make a prostration as long as you would take to recite fifty verses before raising his head. When the mu'adhdhin finished his call for the dawn prayer and the dawn became clear to him.... Then the narrator transmitted the rest of the tradition to the same effect. Some narrators added something more in their version

Reference

Sunan Abi Dawud 1337

In-book

Book 5, Hadith 88