(a) Nafi' (may Allah have mercy on him) narrates from Sayyiduna Ibn Umar (may Allah be pleased with them both) that he made two prostrations in Surah al-Hajj.
(b) It has been narrated to us from Sayyiduna Ali (may Allah be pleased with him) that he made two prostrations in Surah al-Hajj.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الصلاة / 3731