Musannaf Ibn Abi Shayba 9:1215

Abu Usama narrated to us, from Abdullah, from Nafi’, who said: A son of Abdullah ibn Umar married a daughter of Ubaydullah ibn Umar, whose mother was Asma bint Zayd ibn al-Khattab. He (the husband) died, and he had not assigned a dowry (mahr) for her. They (her family) demanded from him (Ibn Umar) the dowry and the inheritance. Ibn Umar said: "She has the inheritance, and there is no dowry for her." They refused that from Ibn Umar, so they appointed Zayd ibn Thabit between them. Zayd said: "She has the inheritance, and there is no dowry for her."