Refer to "Ryoma SAKAMOTO" by Masamichi ASUKAI (Heibonsha, 1975) and "Taisei-hokan (the Restoration of the Imperial rule) and Confidential Imperial Order to Overthrow the Tokugawa Shogunate" by Yoshihisa ISHIO (San-ichi Shobo, 1979).
飛鳥井雅道『坂本龍馬』（平凡社、1975年）・石尾芳久『大政奉還と討幕の密勅』（三一書房、1979年）などを参照。