Hadith.1233 - Hammad ibn Uthman narrated from Imran Al-Halabi, who said
"Imam Jafar ibn Muhammad Al-Sadiq (as) was asked about a man who prays the Jumu’ah prayer as four rak'ahs. Should he recite aloud?
Imam (as) replied: "Yes, and there is Qunoot (a supplication) in the second rak'ah."