(6) The Book of Prayer - Travellers
كتاب صلاة المسافرين وقصرها
(48) Chapter: The clarification that the Qur’an was revealed in seven ahruf (modes of recitation), and clarifying its meaning
(48) باب بَيَانِ أَنَّ الْقُرْآنَ عَلَى سَبْعَةِ أَحْرُفٍ وَبَيَانِ مَعْنَاهُ ‏
Sahih Muslim 819 b 

This hadith has been narrated by Zuhri with the same chain of trans- mitters.

وَحَدَّثَنَاهُ عَبْدُ بْنُ حُمَيْدٍ، أَخْبَرَنَا عَبْدُ الرَّزَّاقِ، أَخْبَرَنَا مَعْمَرٌ، عَنِ الزُّهْرِيِّ، بِهَذَا الإِسْنَادِ.
Reference : Sahih Muslim 819b
In-book reference : Book 6, Hadith 331
USC-MSA web (English) reference : Book 4, Hadith 1786
  (deprecated numbering scheme)