Sunan an-Nasa'i 2352
سنن النسائي#2352SahihIt was narrated from Umm Salamah:That the Messenger of Allah would not fast any two consecutive months except Shaban and Ramadan
Scholarly Authentication
We show the most cautious grade (weakest-wins) as the overall label. Individual scholars graded it as follows:
Abu GhuddahSahih
Al-AlbaniSahih
Zubair Ali ZaiHasan
In-book reference: 22:263