Sahih Muslim Book 4, Hadith Number 2044.

Chapter : Washing of the dead body.

A Hadith like this has been transmitted by Hafsa on the authority of Umm ‘Atiyya with the exception (of these words that the Holy Prophet asked them to wash her dead body): “three times, five times, seven times, or more than that, if you deem fit:” Hafsa (further) said on the authority of Umm ‘Atiyya: We braided (the hair) of her head in three plaits.