references.bib

@article{ehrig2001isomorphie,
  title={Isomorphie, Mono-und Epimorphismen},
  author={Ehrig, Hartmut and Mahr, Bernd and Gro{\ss}e-Rhode, Martin and Cornelius, Felix and Zeitz, Philip and Ehrig, Hartmut and Mahr, Bernd and Gro{\ss}e-Rhode, Martin and Cornlius, Felix and Zeitz, Philip},
  journal={Mathematisch-strukturelle Grundlagen der Informatik},
  pages={479--486},
  year={2001},
  publisher={Springer}
}

@book{mac2013categories,
  title={Categories for the working mathematician},
  author={Mac Lane, Saunders},
  volume={5},
  year={2013},
  publisher={Springer Science \& Business Media}
}