Muwatta Malik 314
موطأ مالك#314SahihYahya related to me from Malik from Da'ud ibn al-Husayn that Ibn Yarbu al-Makhzumi said, "I heard Zayd ibn Thabit say, 'The middle prayer is the prayer of dhuhr
Scholarly Authentication
We show the most cautious grade (weakest-wins) as the overall label. Individual scholars graded it as follows:
Salim al-HilaliMauquf Sahih
In-book reference: 8:28