@article{10_4153_CJM_1967_070_8,
     author = {Nelson, Evelyn},
     title = {Finiteness of {Semigroups} of {Operators} in {Universal} {Algebra}},
     journal = {Canadian journal of mathematics},
     pages = {764--768},
     year = {1967},
     volume = {19},
     number = {1},
     doi = {10.4153/CJM-1967-070-8},
     url = {http://geodesic.mathdoc.fr/articles/10.4153/CJM-1967-070-8/}
}