The uncle of 'Abbaad bin Tamim, 'Abdullah bin Zayd Radiyallahu 'Anhu reports:
"I have seen Rasulullah Sallallahu 'Alayhi Wasallam lying flat on his back in the masjid, with one leg resting on the other. (DE)
English reference (DE): Book 20, Hadith 121 (DE)
Arabic reference (DE): Book 21, Hadith 128 (DE)