For users of LaTeX there is a very good package called tufte-latex for emulating this style. I used this for the writing of the Privacy Engineering book , as an example page below shows:
|Extract from book: Privacy Engineering - |
showing the Tufte style of page layout
There is a Google group for the discussion of the tufte-latex package, but I'll reproduce here my experiences of using this package so maybe a wider audience gets to know about this and how they might too use this excellent LaTeX package.
Originally written 20 July 2014, tufte-latex Google Group
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 Ian Oliver. Privacy Engineering: a data flow and ontological approach. CreateSpace Independent Publishing.