The Book of Fasting
وَحَدَّثَنِي مُحَمَّدُ بْنُ رَافِعٍ، حَدَّثَنَا عَبْدُ الرَّزَّاقِ، أَخْبَرَنَا ابْنُ جُرَيْجٍ، أَخْبَرَنِي عُبَيْدُ، اللَّهِ بْنُ أَبِي يَزِيدَ فِي هَذَا الإِسْنَادِ بِمِثْلِهِ .A hadith like this has been narrated on the authority of 'Ubaidullah b. Abi Yazid
From Sahih Muslim, whose reports the scholars accept as authentic.