(9) باب وُجُوبِ الإِحْدَادِ فِي عِدَّةِ الْوَفَاةِ وَتَحْرِيمِهِ فِي غَيْرِ ذَلِكَ إِلاَّ ثَلاَثَةَ أَيَّامٍ
Umm `Atiyya (Allah be pleased with her) reported that Allah's Messenger (ﷺ) had said:
A woman must not observe mourning for one who had died for more than three (days) except for four months and ten days in the case of her husband. And she must not wear a dyed garment except one of the types made of dyed yarn, or apply collyrium, or touch perfume except a little perfume or incense, when she has been purified after her courses.
Reference: Sahih Muslim 938 c
In-book reference: Book 18, Hadith 85
USC-MSA web (English) reference(deprecated numbering scheme): Book 9, Hadith 3550