How to write Mathematics (1970) [pdf]
Of, course there is Knuth's version of "Mathematical Writing" as well.<p><a href="http://jmlr.csail.mit.edu/reviewing-papers/knuth_mathematical_writing.pdf" rel="nofollow">http://jmlr.csail.mit.edu/reviewing-papers/knuth_mathematica...</a><p>which seems a bit more nut-and-bolts.  This post seems a good compliment.