Abu Dawud
Funerals
Book Number: 014 / Hadith Number: 3214
Narated By Al-Qasim ibn Muhammad ibn AbuBakr : I said to 'Aisha! Mother, show me the grave of the Apostle of Allah (pbuh) 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.