حَدَّثَنِي يَحْيَى، عَنْ مَالِكٍ، عَنْ نَافِعٍ، عَنْ عَبْدِ اللَّهِ بْنِ عُمَرَ، أَنَّ عُمَرَ بْنَ الْخَطَّابِ، قَالَ مَنْ ضَفَرَ رَأْسَهُ فَلْيَحْلِقْ وَلاَ تَشَبَّهُوا بِالتَّلْبِيدِ ‏.‏

Yahya related to me from Malik from Nafi from 'Abdullah ibn 'Umarthat Umar ibn al-Khattab said, "Someone who puts plaits in his hairshould shave his head, and do not plait your hair in such a way thatit seems you have matted it." Translation Not Available

Book Ref: Muwatta Imam Malik Book 20 Hadith 899
Web Ref:  Muwatta Imam Malik Book 20 Hadith 200