مُوَطَّأُ مَالِكٍ
Muwatta Malik 350
Shortening the Prayer
وَحَدَّثَنِي عَنْ مَالِكٍ، عَنْ زَيْدِ بْنِ أَسْلَمَ، عَنْ أَبِيهِ، عَنْ عُمَرَ بْنِ الْخَطَّابِ، مِثْلَ ذَلِكَ .
Yahya related the same as that to me from Malik from Zayd ibn Aslam from his father from Umar ibn al-Khattab.
Arabic/English book reference: Book 9, Hadith 21