Musannaf Ibn Abi Shayba 26:399

Ibn ‘Ulayyah narrated to us, from al-Taymi, from Bakr ibn ‘Abd Allah al-Muzani, that thirty thousand [dirhams] were brought to Ibn ‘Umar. He said—I think he said—"I have emancipated it as a *sa’ibah* (a type of unconditional manumission)." So he ordered that slaves be purchased with it [and set free].