1. M. Barr and C. Wells, Categories for Computer Scientists, Prentice Hall, 1990.
2. C. Ehresmann, Esquisses et types de structures algébriques, Bull. Instit. Polit., Iasi XIV (1968), 1–14.
3. Lecture Notes in Math.;P. Gabriel,1971
4. J.-Y. Girard, Une extension de l'interpretation de Gödel a l'analyse, et son application a l'elimination des coupures dans l'analyse et la theorie des types. In J.E. Fenstad, editor, Proceedings of the Second Scandinavian Logic Symposium, North-Holland Pub. Co., Amsterdam, London, 1971, 63–92.
5. J.-Y. Girard, Proofs and Types, Translated and with appendices by P. Taylor and Y. Lafont, Cambridge University Press, Cambridge, 1989.