Sufyan al-Thawri narrated it from Hisham bin Urwah, from his father (Urwah), that the funeral prayer of Sayyiduna Abu Bakr (may Allah be pleased with him) was offered in the mosque. Abdullah bin al-Walid (may Allah have mercy on him) states that Sufyan al-Thawri (may Allah have mercy on him) also mentioned this hadith.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الجنائز / 7038