The Book of Fasting
وَحَدَّثَنَا إِسْحَاقُ بْنُ إِبْرَاهِيمَ، أَخْبَرَنَا عَبْدُ الرَّزَّاقِ، حَدَّثَنَا مَعْمَرٌ، عَنْ أَيُّوبَ، بِهَذَا الإِسْنَادِ إِلاَّ أَنَّهُ قَالَ عَنِ ابْنِ سَعِيدِ بْنِ جُبَيْرٍ، لَمْ يُسَمِّهِ .This hadith has been narrated on the authority of Ayyub with the same chain of transmitters
From Sahih Muslim, whose reports the scholars accept as authentic.