Mathematica has some basic LaTeX export possibilities built in. However, the LaTeX support is far from optimal and at times quite buggy.
I just came across two issues: Missing support for Subsuperscript and nonsensical \left and \right statements which
are inserted in connection with Abs. I wrote a short python3 script as a workaround (together with Mathematica integration).
Mathematica version:
11.0.0 for Linux x86 (64-bit) (July 28, 2016
Minimal example for the bugs:
The workaround comes as a python3 script texexpression.py, which either takes Mathematica generated LaTeX strings as an argument or
reads them from stdin.
If texexpression.py is in the same directory as your Mathematica file, it can also be called using the Mathematica wrapper fixLatexErrors.
Again the example from above:
As it should be.