Al-Adab Al-Mufrad, Book 48, Hadith 1181 (In-Book) ⓘ
'Imran ibn Muslim said, "I saw Anas ibn Malik sitting like that - cross-legged, with one of his feet over the other one."
حَدَّثَنَا مُحَمَّدُ بْنُ يُوسُفَ، قَالَ: حَدَّثَنَا سُفْيَانُ، عَنْ عِمْرَانَ بْنِ مُسْلِمٍ قَالَ: رَأَيْتُ أَنَسَ بْنَ مَالِكٍ يَجْلِسُ هَكَذَا مُتَرَبِّعًا، وَيَضَعُ إِحْدَى قَدَمَيْهِ عَلَى الأخْرَى.
also referenced under: Hadith 1181 (Reference) & Book 48, Hadith 1181 (English)