@article{05076880,
title = {Closedness properties of internal relations. I. A unified approach to Mal'tsev, unital and subtractive categories.},
journal = {Theory and Applications of Categories [electronic only]},
volume = {16},
year = {2006},
pages = {236-261},
zbl = {1104.18002},
language = {en},
url = {http://dml.mathdoc.fr/item/05076880}
}
Janelidze, Zurab. Closedness properties of internal relations. I. A unified approach to Mal'tsev, unital and subtractive categories.. Theory and Applications of Categories [electronic only], Tome 16 (2006) pp. 236-261. http://gdmltest.u-ga.fr/item/05076880/