The Book of Jihad and Expeditions
وَحَدَّثَنِي أَحْمَدُ بْنُ حَنْبَلٍ، حَدَّثَنَا مُعْتَمِرُ بْنُ سُلَيْمَانَ، عَنْ كَهْمَسٍ، عَنِ ابْنِ بُرَيْدَةَ، عَنْ أَبِيهِ، أَنَّهُ قَالَ غَزَا مَعَ رَسُولِ اللَّهِ صلى الله عليه وسلم سِتَّ عَشْرَةَ غَزْوَةً .It has been narrated by Buraida who heard it from his father that he joined the Messenger of Allah (ﷺ) in sixteen military campaigns
From Sahih Muslim, whose reports the scholars accept as authentic.