كتاب الجهاد والسير
32  
The Book of Jihad and Expeditions
(48)
Chapter: Women who take part in military expeditions are to be given a reward but not a regular share; And the prohibition of killing children of the enemy
(48)
باب النِّسَاءُ الْغَازِيَاتُ يُرْضَخُ لَهُنَّ وَلاَ يُسْهَمُ وَالنَّهْىُ عَنْ قَتْلِ صِبْيَانِ أَهْلِ الْحَرْبِ
Sahih Muslim 1812 h

A similar tradition has been narrated on the authority of Hisham b. Hassan through a different chain of transmitters.

وَحَدَّثَنَا عَمْرٌو النَّاقِدُ، حَدَّثَنَا يَزِيدُ بْنُ هَارُونَ، حَدَّثَنَا هِشَامُ بْنُ حَسَّانَ، بِهَذَا الإِسْنَادِ نَحْوَهُ ‏.‏
Reference : Sahih Muslim 1812h
In-book reference : Book 32, Hadith 173
USC-MSA web (English) reference : Book 19, Hadith 4463
  (deprecated numbering scheme)