All the contents of the doc directory including the articles and the
tutorial are copyright by Sam Aaron unless a specific author is stated
with the comment `# coded by ...` in which case the copyright is
associated with that author (2015) and the content is released under the
CC BY-NC-SA 4.0 license:
All the contents of the doc directory including the articles and the

http://creativecommons.org/licenses/by-nc-sa/4.0/

