Yamamoto:

Distribution of moated settlements and ceramic cultural spheres in eastern Japan Adapted from Ishikawa Hideshi, “Higashi Nihon no kangō shūraku” [Moated settlements of eastern Japan], in Yayoi jidai no shūraku [Settlements of the Yayoi period] (Osaka Prefectural Museum of Yayoi Culture, ed., 2001); Hakkutsu sareta Nihon rettō 2007 [Excavations in the Japanese Archipelago, 2007] (Bunkachō [Agency for Cultural Affairs], ed., Asahi Shimbunsha, 2007).