https://github.com/KaTeX/KaTeX
https://modalwebstore.com/product/equation-editor-pro/
https://zestedesavoir.com/tutoriels/439/des-tableaux-de-variations-et-de-signes-avec-latex/
http://www.holoborodko.com/pavel/quicklatex/
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https://apps.nawouak.net/tex2png/