Sunan Ibn Majah, Book 1, Hadith 472 (In-Book) ⓘ
It was narrated that Salamah bin Akwa' said: "I saw the Messenger of Allah performing ablution, and he wiped his head once."
حَدَّثَنَا مُحَمَّدُ بْنُ الْحَارِثِ الْمِصْرِيُّ، حَدَّثَنَا يَحْيَى بْنُ رَاشِدٍ الْبَصْرِيُّ، عَنْ يَزِيدَ، مَوْلَى سَلَمَةَ عَنْ سَلَمَةَ بْنِ الأَكْوَعِ، قَالَ رَأَيْتُ رَسُولَ اللَّهِ ـ صلى الله عليه وسلم ـ تَوَضَّأَ فَمَسَحَ رَأْسَهُ مَرَّةً .
also referenced under: Hadith 437 (Reference) & Volume 1, Book 1, Hadith 437 (DarusSalam)