Quantizations in a category of relations. Jakobsen, Per K., Lychagin, Valentin V. (2005) Lobachevskii Journal of Mathematics
Quasi locally connected toposes. Bunge, Marta, Funk, Jonathon (2007) Theory and Applications of Categories [electronic only]
Quillen cohomology and Baues-Wirsching cohomology of algebraic, theories M. Jibladze, T. Pirashvili (2006) Cahiers de Topologie et Géométrie Différentielle Catégoriques