Muwatta Malik · Hadith 431

وَحَدَّثَنِي عَنْ مَالِكٍ، أَنَّهُ بَلَغَهُ أَنَّ أَبَا بَكْرٍ، وَعُمَرَ، كَانَا يَفْعَلاَنِ ذَلِكَ ‏.‏

Yahya related to me from Malik that he had heard that Abu Bakr and Umar used to do that

Gradings are classical jarḥ-wa-taʿdīl, name-matched to a rijāl index (not individually re-verified).