Musannaf Ibn Abi Shayba 13:2792

Abu Bakr narrated to us, he said: Ghundar narrated to us, from Shu'bah, who said: I asked al-Hakam and Hammad about pre-emption (shuf'ah). They said: If the house is next to the house, with no road between them, then there is pre-emption in it.