Language:
كتاب الفرائض
85  
Laws of Inheritance (Al-Faraa'id)
(15)
Chapter: The heirs of a lady who dies, leaving two cousins – her maternal brother and her husband.
(15)
باب ابْنَىْ عَمٍّ أَحَدُهُمَا أَخٌ لِلأُمِّ وَالآخَرُ زَوْجٌ
Sahih al-Bukhari 6746

Narrated Ibn `Abbas:

The Prophet (ﷺ) said, "Give the Fara'id (the shares of the inheritance that are prescribed in the Qur'an) to those who are entitled to receive it; and whatever is left should be given to the closest male relative of the deceased."

حَدَّثَنَا أُمَيَّةُ بْنُ بِسْطَامٍ، حَدَّثَنَا يَزِيدُ بْنُ زُرَيْعٍ، عَنْ رَوْحٍ، عَنْ عَبْدِ اللَّهِ بْنِ طَاوُسٍ، عَنْ أَبِيهِ، عَنِ ابْنِ عَبَّاسٍ، عَنِ النَّبِيِّ صلى الله عليه وسلم قَالَ ‏ "‏ أَلْحِقُوا الْفَرَائِضَ بِأَهْلِهَا، فَمَا تَرَكَتِ الْفَرَائِضُ فَلأَوْلَى رَجُلٍ ذَكَرٍ ‏"‏‏.‏
Reference : Sahih al-Bukhari 6746
In-book reference : Book 85, Hadith 23
USC-MSA web (English) reference : Vol. 8, Book 80, Hadith 738
  (deprecated numbering scheme)