add note about latex

doc/README.md

@@ -2,13 +2,31 @@
 To build docs, run `make` in this directory. `make help` lists all targets.
 
 ## Requirements ##
-Sphinx is needed to build doc. Install with `pip install sphinx`.
+Sphinx and Latex is needed to build doc.
+
+**Spinx:**
+```sh
+pip install sphinx
+```
+
+**Latex Ubuntu:**
+```sh
+sudo apt-get install -qq texlive texlive-latex-extra dvipng
+```
+
+**Latex Mac:**
+
+Install the full [MacTex](http://www.tug.org/mactex/) installation or install the smaller [BasicTex](http://www.tug.org/mactex/morepackages.html) and add *ucs* and *dvipng* packages:
+```sh
+sudo tlmgr install ucs dvipng
+```
+
 
 ## Fixing Warnings ##
 
 - "citation not found: R###"
   $ cd doc/build; grep -rin R### .
-  There is probably an underscore after a reference 
+  There is probably an underscore after a reference
   in the first line of a docstring (e.g. [1]_)
 
 - "Duplicate citation R###, other instance in...""