1. Exact categories;Barr,1971
2. Mal'cev, Protomodular, Homological and Semi-Abelian Categories;Borceux,2004
3. Topological semi-abelian algebras;Borceux;Adv. Math.,2005
4. Internal object actions;Borceux;Comment. Math. Univ. Carol.,2005
5. Normalization equivalence, kernel equivalence and affine categories;Bourn,1991