The Book of Pilgrimage
حَدَّثَنَا مُحَمَّدُ بْنُ الْمُثَنَّى، حَدَّثَنِي عَبْدُ الصَّمَدِ، حَدَّثَنَا هَمَّامٌ، حَدَّثَنَا قَتَادَةُ، قَالَ سَأَلْتُ أَنَسًا كَمْ حَجَّ رَسُولُ اللَّهِ صلى الله عليه وسلم قَالَ حَجَّةً وَاحِدَةً وَاعْتَمَرَ أَرْبَعَ عُمَرٍ . ثُمَّ ذَكَرَ بِمِثْلِ حَدِيثِ هَدَّابٍ .Qatada said:I asked Anas (Allah be pleased with him) as to how many Pilgrimages had been performed by Allah's Messenger (ﷺ), and he replied: One Hajj and four `Umras were performed by him. The rest of the hadith is the same
From Sahih Muslim, whose reports the scholars accept as authentic.