كتاب الطهارة
2  
The Book of Purification
(34)
Chapter: The evidence that urine is impure and the obligation to take precautions concerning it
(34)
باب الدَّلِيلِ عَلَى نَجَاسَةِ الْبَوْلِ وَوُجُوبِ الاِسْتِبْرَاءِ مِنْهُ ‏‏
Sahih Muslim 292b

This hadith is transmitted from A'mash by Abmad b. Yusuf al-Azdi, Mu'alla b. Asad, Abd al-Wahid, Sulaiman with the same chain of transmitters but for the words:

" The other did not keep himself safe from being defiled by urine."
حَدَّثَنِيهِ أَحْمَدُ بْنُ يُوسُفَ الأَزْدِيُّ، حَدَّثَنَا مُعَلَّى بْنُ أَسَدٍ، حَدَّثَنَا عَبْدُ الْوَاحِدِ، عَنْ سُلَيْمَانَ الأَعْمَشِ، بِهَذَا الإِسْنَادِ غَيْرَ أَنَّهُ قَالَ ‏ "‏ وَكَانَ الآخَرُ لاَ يَسْتَنْزِهُ عَنِ الْبَوْلِ أَوْ مِنَ الْبَوْلِ ‏"‏ ‏.‏
Reference : Sahih Muslim 292b
In-book reference : Book 2, Hadith 144
USC-MSA web (English) reference : Book 2, Hadith 576
  (deprecated numbering scheme)