@article{03961671, title = {Categorical constructions in graph theory.}, journal = {International Journal of Mathematics and Mathematical Sciences}, volume = {9}, year = {1986}, pages = {1-16}, doi = {10.1155/S0161171286000017}, zbl = {0597.05059}, language = {en}, url = {http://dml.mathdoc.fr/item/03961671} }
Bumby, Richard T.; Latch, Dana May. Categorical constructions in graph theory.. International Journal of Mathematics and Mathematical Sciences, Tome 9 (1986) pp. 1-16. doi : 10.1155/S0161171286000017. http://gdmltest.u-ga.fr/item/03961671/