Sahih Muslim 1488
Sahih Muslim · Book 18: The Book of Divorce · 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
وَحَدَّثَنَا عُبَيْدُ اللَّهِ بْنُ مُعَاذٍ ، حَدَّثَنَا أَبِي ، حَدَّثَنَا شُعْبَةُ ، عَنْ حُمَيْدِ بْنِ نَافِعٍ ، بِالْحَدِيثَيْنِ جَمِيعًا حَدِيثِ أُمِّ سَلَمَةَ فِي الْكُحْلِ وَحَدِيثِ أُمِّ سَلَمَةَ وَأُخْرَى مِنْ أَزْوَاجِ النَّبِيِّ صلى الله عليه وسلم غَيْرَ أَنَّهُ لَمْ تُسَمِّهَا زَيْنَبُ نَحْوَ حَدِيثِ مُحَمَّدِ بْنِ جَعْفَرٍ .
Humaid b. Nafi' narrated two traditions from Umm Salama dealing with collyrium and the other hadith from the wives of Allah's Prophet (ﷺ) except with this that no mention was made of Zainab.