@article{10_21136_CMJ_1989_102299,
     author = {Jakub{\'\i}k, J\'an},
     title = {On some types of kernels of a convergence $l$-group},
     journal = {Czechoslovak Mathematical Journal},
     pages = {239--247},
     publisher = {mathdoc},
     volume = {39},
     number = {2},
     year = {1989},
     doi = {10.21136/CMJ.1989.102299},
     mrnumber = {992131},
     zbl = {0748.06006},
     language = {en},
     url = {http://geodesic.mathdoc.fr/articles/10.21136/CMJ.1989.102299/}
}