- Proofs and types
- The full text of this book by Jean-Yves Girard, Yves Lafont and Paul Taylor, is now available online. Alternatively copies of the original book are available in the library.
- Toposes, triples and theories
- The full text of the new out of print book by Michael Barr and Charles Wells, the authors of Category theory for computing science (see below).
- Category theory for computing science
- Regretably the full text of this book is not available, but there is, nevertheless some useful material in the supplement available via this link, and also the solutions to the exercises.
- Book of proof
- An introduction to the standard methods of proving mathematical theorems. This book is now one of the recommended texts for the part 1A discrete mathematics course, and is freely avalable online.