Language:
كتاب المناقب
61  
Virtues and Merits of the Prophet (pbuh) and his Companions
(20)
Chapter: The Kunya of the Prophet (saws)
(20)
باب كُنْيَةِ النَّبِيِّ صلى الله عليه وسلم
Sahih al-Bukhari 3537

Narrated Anas:

While the Prophet (ﷺ) was in the market, a man called (somebody), "O Abu-l-Qasim!' The Prophet (ﷺ) turned to him and said "Name yourselves after me but do not call yourselves by my Kuniya."

حَدَّثَنَا حَفْصُ بْنُ عُمَرَ، حَدَّثَنَا شُعْبَةُ، عَنْ حُمَيْدٍ، عَنْ أَنَسٍ ـ رضى الله عنه ـ قَالَ كَانَ النَّبِيُّ صلى الله عليه وسلم فِي السُّوقِ فَقَالَ رَجُلٌ يَا أَبَا الْقَاسِمِ‏.‏ فَالْتَفَتَ النَّبِيُّ صلى الله عليه وسلم فَقَالَ ‏ "‏ سَمُّوا بِاسْمِي، وَلاَ تَكْتَنُوا بِكُنْيَتِي ‏"‏‏.‏
Reference : Sahih al-Bukhari 3537
In-book reference : Book 61, Hadith 46
USC-MSA web (English) reference : Vol. 4, Book 56, Hadith 737
  (deprecated numbering scheme)