Sahih (Sahih Muslim)
وَحَدَّثَنَاهُ أَبُو بَكْرِ بْنُ أَبِي شَيْبَةَ، حَدَّثَنَا أَبُو أُسَامَةَ، حَدَّثَنَا هِشَامٌ، بِهَذَا الإِسْنَادِ وَزَادَ تَعْنِي أَبَا بَكْرٍ وَالزُّبَيْرَ .
This hadith has been narrated on the authority of Hishan through the same chain of transmitters but with this addition (that by both fathers of yours) he meant Abu Bakr and Zubair