@article{1102945267, author = {Freese, Ralph and Nation, J. B.}, title = {Congruence lattices of semilattices.}, journal = {Pacific J. Math.}, volume = {49}, number = {2}, year = {1973}, pages = { 51-58}, language = {en}, url = {http://dml.mathdoc.fr/item/1102945267} }
Freese, Ralph; Nation, J. B. Congruence lattices of semilattices.. Pacific J. Math., Tome 49 (1973) no. 2, pp. 51-58. http://gdmltest.u-ga.fr/item/1102945267/