Musnad Abu Ya'la al-Mawsili 154:197

'Abdullah narrated to us, Juwayriyah narrated to us, Nafi' narrated to us, that 'Abdullah ibn 'Umar informed him that the Messenger of Allah (may Allah bless him and grant him peace) sent a military expedition to Najd, among whom was 'Abdullah. They obtained much spoils of war, and their shares were twelve camels each, and he (the Prophet) gave each man of them an extra portion (nafal).