From Sahih Bukhari (Hadith 4530):
Narrated Ibn Az-Zubair:I said to `Uthman bin `Affan (while he was collecting the Qur'an) regarding the Verse:-- "Those of you who die and leave wives ..." (2.240) "This Verse was abrogated by another Verse. So why should you write it? (Or leave it in the Qur'an)?" `Uthman said. "O son of my brother! I will not shift anything of it from its place
Reference: Bukhari 4530