مُوَطَّأُ مَالِكٍ
Muwatta Malik 19
The Times of Prayer
حَدَّثَنِي يَحْيَى، عَنْ مَالِكٍ، عَنْ نَافِعٍ، أَنَّ عَبْدَ اللَّهِ بْنَ عُمَرَ، كَانَ يَقُولُ دُلُوكُ الشَّمْسِ مَيْلُهَا .
Yahya related to me from Malik from Nafi that Abdullah ibn Umar used to say, "Duluk ash-shams begins from when the sun passes the meridian."
Arabic/English book reference: Book 1, Hadith 19