Sunan Ibn Majah 436
سنن ابن ماجه#436SahihIt was narrated from 'Ali that:The Messenger of Allah wiped his head once
Scholarly Authentication
We show the most cautious grade (weakest-wins) as the overall label. Individual scholars graded it as follows:
Al-AlbaniSahih
Muhammad Fouad Abd al-BaqiSahih
Zubair Ali ZaiSahih
In-book reference: 1:170