Ibn Ishaq said: Among the women who were present at (the pledge of) al-Aqabah were Lubaysah and her sister, the two daughters of Ka'b bin Amr bin Awf, and she is Umm Umarah, whose son was seized by Musaylimah (the Liar).
Hadith Referenceالمعجم الكبير للطبراني / مسند النساء / 21511