وَحَدَّثَنِي عَنْ مَالِكٍ، عَنْ نَافِعٍ، أَنَّ عَبْدَ اللَّهِ بْنَ عُمَرَ، كَانَ لاَ يَصُومُ فِي السَّفَرِ ‏.‏

Yahya related to me from Malik from Nafi that Abdullah ibn Umarused not to fast while travelling. Translation Not Available

Book Ref: Muwatta Imam Malik Book 18 Hadith 659
Web Ref:  Muwatta Imam Malik Book 18 Hadith 25