Urwah bin al-Zubayr (may Allah have mercy on him) narrates from Sayyiduna Mughirah bin Shu'bah (may Allah be pleased with him) that Umar bin al-Khattab (may Allah be pleased with him) asked them for a ruling about imlas al-mar'ah. Mughirah bin Shu'bah (may Allah be pleased with him) said: "The Messenger of Allah (peace and blessings be upon him) decided a slave (ghurrah) in it." Then Muhammad bin Maslamah al-Ansari (may Allah be pleased with him) testified for him that the Messenger of Allah (peace and blessings be upon him) had made this same decision in it.
Hadith Referenceالمعجم الكبير للطبراني / باب الميم / 18195