Sunan an-Nasa'i 2368
سنن النسائي#2368HasanIt was narrated that 'Abdullah bin Masud said:"The Messenger of Allah used to fast three days in the middle of every month, and he rarely did not fast on Friday
Scholarly Authentication
We show the most cautious grade (weakest-wins) as the overall label. Individual scholars graded it as follows:
Abu GhuddahHasan
Al-AlbaniHasan
Zubair Ali ZaiIsnaad Hasan
In-book reference: 22:279