سنن ابي داود
Sunan Abi Dawud
أبواب تفريع استفتاح الصلاة
Prayer (Tafarah Abwab Estaftah Assalah)
باب السُّجُودِ عَلَى الأَنْفِ وَالْجَبْهَةِ
Chapter: Prostrating On The Nose And Forehead.
Hadith 895
The above mentioned tradition has also been transmitted by Mamar through a different chain of narrators to the same effect.
