@article{10_4153_CJM_1975_065_1,
     author = {Viola-Prioli, Jorge E.},
     title = {When is {Every} {Kernel} {Functor} {Idempotent?}},
     journal = {Canadian journal of mathematics},
     pages = {545--554},
     year = {1975},
     volume = {27},
     number = {3},
     doi = {10.4153/CJM-1975-065-1},
     url = {http://geodesic.mathdoc.fr/articles/10.4153/CJM-1975-065-1/}
}