Musannaf Ibn Abi Shayba 5:962

'Affan narrated to us, he said: Hammad ibn Salamah narrated to us, he said: Humayd informed us, from Hayyan al-Sulami, who said: I said to Ibn 'Umar: "The tax collectors (musaddiqu) of Ibn al-Zubayr come to me and take the charity (sadaqah), and the tax collectors of Najdah come and take [it]." He said: "Whichever of them you give it to, it suffices you."