The Book of Mosques and Places of Prayer
حَدَّثَنِي أَحْمَدُ بْنُ عَبْدِ الرَّحْمَنِ بْنِ وَهْبٍ، حَدَّثَنِي عَمِّي عَبْدُ اللَّهِ، حَدَّثَنِي دَاوُدُ بْنُ قَيْسٍ، عَنْ زَيْدِ بْنِ أَسْلَمَ، بِهَذَا الإِسْنَادِ وَفِي مَعْنَاهُ قَالَ " يَسْجُدُ سَجْدَتَيْنِ قَبْلَ السَّلاَمِ " . كَمَا قَالَ سُلَيْمَانُ بْنُ بِلاَلٍ .This hadith has been narrated by Zaid b. Aslam with the same chain of transmitters and he said:He should perform two prostrations before the salutation, as it was mentioned by Sulaiman b. Bilal
From Sahih Muslim, whose reports the scholars accept as authentic.