Musannaf Ibn Abi Shayba 18:1055

Abu Bakr narrated to us, he said: Abd al-Rahim narrated to us, from Hajjaj, from Ibn Abi Mulaykah, from Nafi’ ibn al-Harith, who said: I wrote to Umar asking him about a man who broke one of his two forearm bones. Umar wrote back to me that in it there are two young she-camels (haqqatayn bakratayn).