كتاب الطلاق
18  
The Book of Divorce
(9)
Chapter: The Obligation to mourn during the 'Iddah following the death of one's husband, but it is forbidden to mourn for more than three days in other cases
(9)
باب وُجُوبِ الإِحْدَادِ فِي عِدَّةِ الْوَفَاةِ وَتَحْرِيمِهِ فِي غَيْرِ ذَلِكَ إِلاَّ ثَلاَثَةَ أَيَّامٍ
Sahih Muslim 938 d

A hadith like this has been narrated on the authority of Hisham with the same chain of narrators but with a slight variation of words.

وَحَدَّثَنَاهُ أَبُو بَكْرِ بْنُ أَبِي شَيْبَةَ، حَدَّثَنَا عَبْدُ اللَّهِ بْنُ نُمَيْرٍ، ح وَحَدَّثَنَا عَمْرٌو النَّاقِدُ، حَدَّثَنَا يَزِيدُ بْنُ هَارُونَ، كِلاَهُمَا عَنْ هِشَامٍ، بِهَذَا الإِسْنَادِ وَقَالاَ ‏ "‏ عِنْدَ أَدْنَى طُهْرِهَا نُبْذَةً مِنْ قُسْطٍ وَأَظْفَارٍ ‏"‏ ‏.‏
Reference : Sahih Muslim 938d
In-book reference : Book 18, Hadith 86
USC-MSA web (English) reference : Book 9, Hadith 3551
  (deprecated numbering scheme)