Hudhayfah Radiyallahu 'Anhu says:
"When Rasulullah Sallallahu 'Alayhi Wasallam lay down on a bed, he recited: Allahurmma bi-ith-mika a-mutu wa ahyaa.Translation... O Allah! In Thy name do I live and die".When he awakened he recited this du'aa: Alhamdulillaahil ladhi ahyaanaa ba'da rnaa amaatana wa-ilayhin nushur.Translation...'Praise be to Allah Who restored unto us life, having caused us to die and unto Him shall be the Resurrection"'.
English reference: Book 38, Hadith 243
Arabic reference: Book 39, Hadith 256