Sunan an-Nasa'i, Volume 6, Book 48, Hadith 5138 (DarusSalam) ⓘ
It was narrated that Nafi' said: "When Ibn 'Umar burned incense he would burn Al-Uluwwah that was not mixed with anything else, or camphor mixed with some Al-Uluwwah. Then he said: 'This is what the Messenger of Allah [SAW] used to burn.'"
أَخْبَرَنَا أَحْمَدُ بْنُ عَمْرِو بْنِ السَّرْحِ أَبُو طَاهِرٍ، قَالَ أَنْبَأَنَا ابْنُ وَهْبٍ، قَالَ أَخْبَرَنِي مَخْرَمَةُ، عَنْ أَبِيهِ، عَنْ نَافِعٍ، قَالَ كَانَ ابْنُ عُمَرَ إِذَا اسْتَجْمَرَ اسْتَجْمَرَ بِالأُلُوَّةِ غَيْرَ مُطَرَّاةٍ وَبِكَافُورٍ يَطْرَحُهُ مَعَ الأُلُوَّةِ ثُمَّ قَالَ هَكَذَا كَانَ يَسْتَجْمِرُ رَسُولُ اللَّهِ صلى الله عليه وسلم .
also referenced under: Hadith 5135 (Reference) & Book 48, Hadith 96 (In-Book)