كتاب الحج
15  
The Book of Pilgrimage
(7)
Chapter: It is recommended to apply perfume just before entering Ihram, and it is recommended to use Musk, and it does not matter if its glistening traces remain
(7)
باب الطِّيبِ لِلْمُحْرِمِ عِنْدَ الإِحْرَامِ ‏
Sahih Muslim 1190 h

'A'isha (Allah be pleased with her) reported:

I still seem to see the glistening of musk (in the parting of the head) of the Messenger of Allah (ﷺ) while he was in the state of Ihram.
حَدَّثَنَا قُتَيْبَةُ بْنُ سَعِيدٍ، حَدَّثَنَا عَبْدُ الْوَاحِدِ، عَنِ الْحَسَنِ بْنِ عُبَيْدِ اللَّهِ، حَدَّثَنَا إِبْرَاهِيمُ، عَنِ الأَسْوَدِ، قَالَ قَالَتْ عَائِشَةُ رضى الله عنها كَأَنِّي أَنْظُرُ إِلَى وَبِيصِ الْمِسْكِ فِي مَفْرِقِ رَسُولِ اللَّهِ صلى الله عليه وسلم وَهُوَ مُحْرِمٌ ‏.‏
Reference : Sahih Muslim 1190h
In-book reference : Book 15, Hadith 49
USC-MSA web (English) reference : Book 7, Hadith 2695
  (deprecated numbering scheme)