(7) باب قضاء الحاجة
and its Asl (original source) is in Abu Da'ud and At-Tirmidhi and Ibn Khuzaima graded it Sahih (sound) through Abu Huraira (rad) without mentioning the "stones".] (ES)
Reference (ES): Bulugh al-Maram 108 (ES)
In-book reference (ES): Book 1, Hadith 127 (ES)
English translation (ES): Book 1, Hadith 114 (ES)