Urwah (may Allah have mercy on him) said: "Among the names of those who were martyred on the day of al-Yamamah, from the Ansar, then from Banu al-Harith bin al-Khazraj: Thabit bin Qays bin Shammas."
Hadith Referenceالمعجم الكبير للطبراني / باب الثاء / 1292