Funerals (Al-Janaa'iz)
Bukhari :: Book 2 :: Volume 23 :: Hadith 369
Narrated Muhammad bin Sirin:
One of the sons of Um 'Atiyya died, and when it was the third day she asked for a yellow perfume and put it over her body, and said, "We were forbidden to mourn for more than three days except for our husbands."