@article{10_4153_CJM_1980_087_6,
     author = {Day, Alan and Freese, Ralph},
     title = {A {Characterization} of {Identities} {Implying} {Congruence} {Modularity} {I}},
     journal = {Canadian journal of mathematics},
     pages = {1140--1167},
     year = {1980},
     volume = {32},
     number = {5},
     doi = {10.4153/CJM-1980-087-6},
     url = {http://geodesic.mathdoc.fr/articles/10.4153/CJM-1980-087-6/}
}