Funerals (Kitab Al-Jana'iz)
Dawud :: Book 20 : Hadith 3214
Narrated Al-Qasim ibn Muhammad ibn AbuBakr:
I said to Aisha! Mother, show me the grave of the Apostle of Allah (peace_be_upon_him) and his two Companions (Allah be pleased with them). She showed me three graves which were neither high nor low, but were spread with soft red pebbles in an open space.