‏اللباس والزينة‏ : Hadeeth No:5289 Ibn Umar reported that Allaah's Messenger (sallAllaahu alayhi wa sallam) forbade Qaza. I said to Nafi: What is Qaza'? He said: This means having a part of a boy's head shaved and leaving a part unshaven....

‏الجهاد والسير‏ : Hadeeth No:4463 A similar tradition has been narrated on the authority of Hisham b. Hassan through a different chain of transmitters....