@book{maclane,
    author = {Mac Lane, Saunders},
    title = {Categories for the Working Mathematician},
    year = 1971,
    publisher = {Springer-Verlag New York, Inc.},
    langid = {english}
}
@book{joyofcats,
    author = {Adámek, Jiří and Herrlich, Horst and Strecker, George},
    title = {Abstract and Concrete Categories: The Joy of Cats},
    year = {1990},
    publisher = {John Wiley \& Sons, Inc.},
    langid = {english}
}
@article{one-universe,
    author = {Mac Lane, Saunders},
    title = {One universe as a foundation for category theory},
    year = {1969},
    journaltitle = {Reports of the Midwest Category Seminar III. Lecture Notes in Mathematics},
    volume = {106},
    publisher = {Springer},
    doi = {10.1007/BFb0059147},
    langid = {english}
}
@book{riehl,
    author = {Emily Riehl},
    title = {Category Theory in Context},
    langid = {english}
}