1. 2018. What are XeTeX and LuaTeX? https://texfaq.org/FAQ-xetex-luatex
2. 2022. Starting a New Era with 11 Million Users and 100 Million Projects. https://www.overleaf.com/blog/starting-a-new-era-with-11-million-users-and-100-million-projects
3. 2023. Category Taxonomy.
4. 2023. History of TeX. https://www.tug.org/whatis.html
5. 2023. ignoring space after \eqno #1059. https://github.com/latex3/latex2e/issues/1059