There is a guidebook about the seven wise men in Saga by Hiroshi FUKUOKA "Bakumatsu (the last days of Tokugawa Shogunate) Restoration in Saga: The life of eight wise men" (Shutsumondo Publisher), which also included descriptions of Fukushima's real elder brother Shinyo EDAYOSHI in addition to those of the seven wise men.
なお案内書に、副島の実兄の枝吉神陽を加えた福岡博『佐賀の幕末維新八賢伝』（出門堂）がある。