0Book 6
وَحَدَّثَنِيهِ إِسْحَاقُ بْنُ مَنْصُورٍ، أَخْبَرَنَا عُبَيْدُ اللَّهِ بْنُ مُوسَى، عَنْ سُفْيَانَ، بِهَذَا الإِسْنَادِ وَقَالَ صَوْمُ شَهْرَيْنِ .
This hadith has been narrated on the authority of Sufyan with the same chain of transmitters in which it is said:
” Fasting of two months.”
USC-MSA web (English) reference