Tamio, Nakamura (3 January 2007). "The History of Bogu". Jikishin Kage-ryu Kenjutsu. Archived from the original on 18 February 2020. Retrieved 23 August 2020.
Tamio, Nakamura (3 January 2007). "The History of Bogu". Jikishin Kage-ryu Kenjutsu. Archived from the original on 18 February 2020. Retrieved 23 August 2020.