Hancock, H. Irving (1905). The Complete Kano Jiu-Jitsu (Judo). New York: G. P. Putnam & Sons. p. 544. See details, including the original book cover here.
hansdejong.biz
Ben Stone. In the Name of the Father: An interview with Hans de Jong Shihan. Blitz Australasian Martial Arts Magazine, Volume 20, Number 8, page 26. Images by Charlie Suriano, Copyright Blitz Publication. See page 1, page 2, page 3, and page 4.
