كتاب الجنائز
11  
The Book of Prayer - Funerals
(12)
Chapter: Washing the deceased
(12)
باب فِي غَسْلِ الْمَيِّتِ ‏
Sahih Muslim 939 d

A hadith like this has been transmitted by Hafsa on the authority of Umm 'Atiyya with the exception (of these words that the 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.
وَحَدَّثَنَا قُتَيْبَةُ بْنُ سَعِيدٍ، حَدَّثَنَا حَمَّادٌ، عَنْ أَيُّوبَ، عَنْ حَفْصَةَ، عَنْ أُمِّ عَطِيَّةَ، ‏.‏ بِنَحْوِهِ غَيْرَ أَنَّهُ قَالَ ‏ "‏ ثَلاَثًا أَوْ خَمْسًا أَوْ سَبْعًا أَوْ أَكْثَرَ مِنْ ذَلِكِ إِنْ رَأَيْتُنَّ ذَلِكِ ‏"‏ ‏.‏ فَقَالَتْ حَفْصَةُ عَنْ أُمِّ عَطِيَّةَ وَجَعَلْنَا رَأْسَهَا ثَلاَثَةَ قُرُونٍ ‏.‏
Reference : Sahih Muslim 939d
In-book reference : Book 11, Hadith 49
USC-MSA web (English) reference : Book 4, Hadith 2044
  (deprecated numbering scheme)