@article{MAN_1985__270_182943,
     author = {Harvey Cohn},
     title = {Iterated {Ring} {Class} {Fields} and the {168-Tesselation.}},
     journal = {Mathematische Annalen},
     pages = {69--78},
     publisher = {mathdoc},
     volume = {270},
     year = {1985},
     zbl = {0559.12007},
     url = {http://geodesic.mathdoc.fr/item/MAN_1985__270_182943/}
}