Musnad Ahmad 1153:2062

Rawh narrated to us, Shu'bah narrated to us, he said: Al-Hakam, Hammad, Mansur, and Sulayman informed us, from Ibrahim, from Al-Aswad, from Aisha, that she said: "It is as if I am looking at the glistening of the perfume in the parting of the hair of the Messenger of Allah, may Allah bless him and grant him peace, while he was in the state of Ihram." Sulayman said: "In his hair." Mansur said: "In the roots of his hair." Al-Hakam and Hammad said: "In the parting of his hair."