مُوَطَّأُ مَالِكٍ
Muwatta Malik 174
Prayer
وَحَدَّثَنِي عَنْ مَالِكٍ، عَنْ نَافِعٍ، أَنَّ عَبْدَ اللَّهِ بْنَ عُمَرَ، كَانَ إِذَا صَلَّى وَحْدَهُ يَقْرَأُ فِي الأَرْبَعِ جَمِيعًا فِي كُلِّ رَكْعَةٍ بِأُمِّ الْقُرْآنِ وَسُورَةٍ مِنَ الْقُرْآنِ وَكَانَ يَقْرَأُ أَحْيَانًا بِالسُّورَتَيْنِ وَالثَّلاَثِ فِي الرَّكْعَةِ الْوَاحِدَةِ مِنْ صَلاَةِ الْفَرِيضَةِ وَيَقْرَأُ فِي الرَّكْعَتَيْنِ مِنَ الْمَغْرِبِ كَذَلِكَ بِأُمِّ الْقُرْآنِ وَسُورَةٍ سُورَةٍ .
Yahya related to me from Malik from Nafi that Abdullah ibn Umar used to recite in all four rakas as when he prayed alone - in every raka the umm al-Qur'an and another sura from the Qur'an. Sometimes he would recite two or three suras in one raka in the obligatory prayer. Similarly, he recited the umm al-Qur'an and two suras in the first two rakas of maghrib.
Arabic/English book reference: Book 3, Hadith 27