Sahih Muslim 719
Sahih Muslim · Book 6: The Book of Prayer - Travellers · It is recommended to pray Duha, the least of which is two rak`ah, the best of which is eight, and the average of which is four or six, and encouragement to do so regularly
وَحَدَّثَنَا إِسْحَاقُ بْنُ إِبْرَاهِيمَ ، وَابْنُ، بَشَّارٍ جَمِيعًا عَنْ مُعَاذِ بْنِ هِشَامٍ ، قَالَ حَدَّثَنِي أَبِي ، عَنْ قَتَادَةَ ، بِهَذَا الإِسْنَادِ مِثْلَهُ .
A hadith like this has been narrated by Qatada with the same chain of transmitters.