@article{CMUC_1971__12_1_a10,
     author = {H\'ajkov\'a, Marie},
     title = {The lattice of bi-numerations of arithmetic. {I.}},
     journal = {Commentationes Mathematicae Universitatis Carolinae},
     pages = {81--104},
     publisher = {mathdoc},
     volume = {12},
     number = {1},
     year = {1971},
     mrnumber = {0284336},
     zbl = {0216.28901},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/CMUC_1971__12_1_a10/}
}