@Booklet{tttikz,
  title =        {The {TikZ} and {PGF} Packages},
  author =    {Till Tantau},
  howpublished = {\url{https://mirrors.dotsrc.org/ctan/graphics/pgf/base/doc/pgfmanual.pdf}}}
@Book{tikz,
  author =       {Till Tantau},
  title =        {The {TikZ} and {PGF} Packages},
  publisher =    {\url{https://mirrors.dotsrc.org/ctan/graphics/pgf/base/doc/pgfmanual.pdf}},
  year =         2023}
@InBook{eijkhout:toksstack,
  author =       {Victor Eijkhout},
  title =        {{\TeX} by Topic},
  chapter =      {14.5.1},
  publisher =    {\url{https://github.com/VictorEijkhout/tex-by-topic/raw/main/TeXbyTopic.pdf}},
  year =         2019}
@InBook{eijkhout:hop,
  author =       {Victor Eijkhout},
  title =        {{\TeX} by Topic},
  chapter =      {13.8.6},
  publisher =    {\url{https://github.com/VictorEijkhout/tex-by-topic/raw/main/TeXbyTopic.pdf}},
  year =         2019}

@Misc{overleaf:classpackage,
  author =       {Overleaf},
  title =        {Understanding packages and class files},
  howpublished = {\url{https://www.overleaf.com/learn/latex/Understanding_packages_and_class_files}}}