The Book of Prayer - Friday
وَحَدَّثَنَا يَحْيَى بْنُ يَحْيَى، وَمُحَمَّدُ بْنُ رُمْحٍ، قَالاَ أَخْبَرَنَا اللَّيْثُ، ح وَحَدَّثَنَا قُتَيْبَةُ، حَدَّثَنَا لَيْثٌ، عَنْ نَافِعٍ، عَنْ عَبْدِ اللَّهِ، أَنَّهُ كَانَ إِذَا صَلَّى الْجُمُعَةَ انْصَرَفَ فَسَجَدَ سَجْدَتَيْنِ فِي بَيْتِهِ ثُمَّ قَالَ كَانَ رَسُولُ اللَّهِ صلى الله عليه وسلم يَصْنَعُ ذَلِكَ .Nafi' reported that when 'Abdullah (b. 'Umar) observed the Friday prayer and came back he observed two rak'ahs in his house, and then said:The Messenger of Allah (may peace be updn him) used to do this
From Sahih Muslim, whose reports the scholars accept as authentic.