Abu Sa'eed Khudari Radiyallahu 'Anhu says:
"When Rasuluilah Sallallahu 'Alayhi Wasallam sat in the rnasjid, he sat in the qarfasaa posture' (PT)
English reference (PT): Book 20, Hadith 122 (PT)
Arabic reference (PT): Book 21, Hadith 129 (PT)