Musnad Abu Ya'la al-Mawsili 150:428

Hawthara narrated to us, Hammad bin Salama narrated to us, from Hisham bin Urwa, from Urwa: That the Messenger of Allah (may Allah bless him and grant him peace) flogged those who said about Aisha what they said, eighty [lashes] each: Hassan bin Thabit, Mistah bin Uthatha, and Hamna bint Jahsh.