Musnad Ahmad 1250:8

Ibn Numayr narrated to us, he said: Hisham narrated to us, from Hafsa bint Sirin, from Umm Atiyyah, who said: The Messenger of Allah (peace and blessings of Allah be upon him) said: "A woman shall not observe mourning for a deceased person for more than three days, except for a husband, for she shall observe mourning for him for four months and ten days. She shall not wear dyed clothing, except for 'asb (garments dyed with yarn before weaving), nor shall she apply kohl, nor shall she apply perfume, except when she is at the end of her period of purity, using a small amount of qist (costus) and azfar (a type of incense)."