LaTeX command references and examples

I'm not sure this is *the* reference, but here’s a Latex help file:

• http://www.emerson.emory.edu/services/latex/latex_toc.html

There’s also a Postscript version available on the site for easier printing.

This PDF is good:

• https://www.bu.edu/math/files/2013/08/LongTeX1.pdf

Here are a few more:

• LaTeX2e unofficial reference manual at tug.org
• http://www.faqs.org/faqs/tex-faq/
• https://en.wikibooks.org/wiki/LaTeX/Command_Glossary (ugly, but helpful)
• The ShareLaTeX documentation home