1. N.H.F. Beebe. 25 Years of TeX and Metafont: Looking back and looking forward—TUG2003 keynote address. TUGboat 25(1):7–30, 2004. https://tug.org/TUGboat/tb25-1/beebe-2003keynote.pdf
2. B. Donald. The nih package, 2005-06-01. https://ctan.org/pkg/nih
3. D. Els, S. Fear. The booktabs package, version 1.61803398, 2020. https://ctan.org/pkg/booktabs
4. Free Software Foundation. What is free software?, Feb. 2021. https://www.gnu.org/philosophy/free-sw.en.html
5. H. Hagen. LuaTeX: Howling to the moon. TUGboat 26(2):152–157, 2005. https://tug.org/TUGboat/tb26-2/hagen.pdf