@article{03979088, title = {A digraph equation for homomorphic images.}, journal = {International Journal of Mathematics and Mathematical Sciences}, volume = {9}, year = {1986}, pages = {409-411}, doi = {10.1155/S0161171286000510}, zbl = {0606.05030}, language = {en}, url = {http://dml.mathdoc.fr/item/03979088} }
Girse, Robert D.; Gillman, Richard A. A digraph equation for homomorphic images.. International Journal of Mathematics and Mathematical Sciences, Tome 9 (1986) pp. 409-411. doi : 10.1155/S0161171286000510. http://gdmltest.u-ga.fr/item/03979088/