Nafi' narrates from Ibn Umar (may Allah be pleased with them both) that he said: I heard the Prophet (peace and blessings be upon him) say: "When one of you is in the mosque on Friday and becomes drowsy, let him change his place."
This hadith is counted among the solitary narrations (afrad) of Muhammad bin Ishaq bin Yasar, and it has also been narrated through another route from Nafi'.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الجمعة / 5925