Typesetting Mathematics According to the ISO Standard by Nick Higham.
From the post:
In The Princeton Companion to Applied Mathematics we used the conventions that the constants e (the base of the natural logarithm) and i (the imaginary unit), and the d in derivatives and integrals, are typeset in an upright font. These conventions are part of an ISO standard, ISO 80000-2:2009. The standard is little-known, though there is an excellent article about it in TUGboat by Claudio Beccari, and Kopka and Daly’s A Guide to
has a page on the standard (in section 7.4.10 of the fourth edition and section 5.4.10 of the third edition).
Nick mentions that you can get a copy of ISO 80000-2:2009 for about $150, and he also says:
However, it is easy to find a freely downloadable version via a Google search.
Let’s don’t be coy about this sort of thing: try http://www.ise.ncsu.edu/jwilson/files/mathsigns.pdf
Every time an illegitimate privilege is acknowledged, it grows stronger.
I refuse to confer any legitimacy or recognition of legitimacy to restricted access to ISO 80000-2:2009.
And you?