Sunan an-Nasa'i, Book 22, Hadith 195 (In-Book) ⓘ
It was narrated that 'Abdur-Rahman bin 'Awf said: "It is said that fasting while traveling is like not fasting while a resident." (Daif)
أَخْبَرَنَا مُحَمَّدُ بْنُ أَبَانَ الْبَلْخِيُّ، قَالَ حَدَّثَنَا مَعْنٌ، عَنِ ابْنِ أَبِي ذِئْبٍ، عَنِ الزُّهْرِيِّ، عَنْ أَبِي سَلَمَةَ بْنِ عَبْدِ الرَّحْمَنِ، عَنْ عَبْدِ الرَّحْمَنِ بْنِ عَوْفٍ، قَالَ يُقَالُ الصِّيَامُ فِي السَّفَرِ كَالإِفْطَارِ فِي الْحَضَرِ .
also referenced under: Hadith 2284 (Reference) & Volume 3, Book 22, Hadith 2286 (DarusSalam)