Sahih Muslim , Book 4, Hadith 1915 (USC-MSA) ⓘ
Abu Huraira reported Allah's Messenger as saying: When any one of you observes the Jumu'a prayer (two obligatory rak'ahs in congregation), he should observe four (rak'ahs) afterwards.
وَحَدَّثَنَا يَحْيَى بْنُ يَحْيَى، أَخْبَرَنَا خَالِدُ بْنُ عَبْدِ اللَّهِ، عَنْ سُهَيْلٍ، عَنْ أَبِيهِ، عَنْ أَبِي، هُرَيْرَةَ قَالَ قَالَ رَسُولُ اللَّهِ صلى الله عليه وسلم " إِذَا صَلَّى أَحَدُكُمُ الْجُمُعَةَ فَلْيُصَلِّ بَعْدَهَا أَرْبَعًا " .
also referenced under: Book 7, Hadith 86 (In-Book) & Hadith 881 (Reference)