@article{10_4153_CJM_1977_006_6,
     author = {Choe, T. H. and Hong, Y. H.},
     title = {Extensive {Subcategories} in {Universal} {Topological} {Algebras}},
     journal = {Canadian journal of mathematics},
     pages = {71--76},
     year = {1977},
     volume = {29},
     number = {1},
     doi = {10.4153/CJM-1977-006-6},
     url = {http://geodesic.mathdoc.fr/articles/10.4153/CJM-1977-006-6/}
}