Musnad Ahmad 1301:12

Yahya ibn Ghaylan narrated to us, he said: Rashdin narrated to us, he said: Amr ibn al-Harith narrated to me, from Sa'id ibn Abi Hilal, from Umar al-Dimashqi, that an informant informed him, from Umm al-Darda, from Abu al-Darda, that he said: "I prostrated with the Prophet, may Allah bless him and grant him peace, eleven prostrations, among them [the prostration in] al-Najm."