Hadithcore
Mishkat al-Masabih, 1668

Zuhri said that Salim reported his father as saying, “I saw God’s messenger, Abu Bakr and ‘Umar walking in front of the bier.” Ahmad, Abu Dawud, Tirmidhi, Nasa'i and Ibn Majah transmitted it, and Tirmidhi said the traditionists seem to consider it is in <i>mursat</i> form.

وَعَنِ الزُّهْرِيِّ عَنْ سَالِمٍ عَنْ أَبِيهِ قَالَ: رَأَيْتُ رَسُولَ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ وَأَبَا بَكْرٍ وَعُمَرَ يَمْشُونَ أَمَامَ الْجَنَازَةِ. رَوَاهُ أَحْمَدُ وَأَبُو دَاوُدَ وَالتِّرْمِذِيُّ وَالنَّسَائِيُّ وَابْنُ مَاجَهْ وَقَالَ التِّرْمِذِيُّ وَأَهْلُ الْحَدِيثِ كَأَنَّهُمْ يَرَوْنَهُ مُرْسَلًا

References1 variant
In-Book Reference
Book 5, Hadith 143