Hadith from Al-Bukhari and Muslim:
Abdullah bin `Umar (May Allah be pleased with them) reported: I performed along with the Prophet (Peace be upon him) two Rak`ah (Sunnah prayer) after the Jumu’ah prayer.
[Al-Bukhari and Muslim].

Hadith from Muslim:
Abu Hurairah (May Allah be pleased with him)reported: The Messenger of Allah (Peace be upon him) said, “If anyone of you performs the Friday prayer, he should perform four Rak`ah (Sunnah) after it.”
[Muslim].