The Book of Mosques and Places of Prayer
وَحَدَّثَنَاهُ ابْنُ رَافِعٍ، أَخْبَرَنَا ابْنُ أَبِي فُدَيْكٍ، أَخْبَرَنَا الضَّحَّاكُ، عَنْ نَافِعٍ، عَنِ ابْنِ عُمَرَ، عَنِ النَّبِيِّ صلى الله عليه وسلم قَالَ " بِضْعًا وَعِشْرِينَ " .Ibn 'Umar reported from the Messenger of Allah (ﷺ) as some and twenty (degrees)
From Sahih Muslim, whose reports the scholars accept as authentic.