The following literature is optional for the scope of ontology engineering, but you may find of interest if you would like to design your own logic, for instance.
- Hedman, S. A first course in logic—an introduction to model theory, proof theory, computability, and complexity. Oxford: Oxford University Press. 2004.
- Solow, D. How to read and do proofs. 4th Ed. Wiley. 2005.