Abu Ishaq said that Sayyiduna Ibn Mas'ud (may Allah be pleased with him) used to pray four rak'ahs before the Friday prayer and four rak'ahs after it. Abu Ishaq said: "And Sayyiduna Ali (may Allah be pleased with him) used to pray six rak'ahs after the Friday prayer."
Hadith Referenceالمعجم الكبير للطبراني / باب العين / 9521