@article{MZ_1969__112_171228,
     author = {Benno Artmann},
     title = {Hjelmslev-Ebenen mit verfeinerten {Nachbarschaftsrelationen.}},
     journal = {Mathematische Zeitschrift},
     pages = {163--180},
     publisher = {mathdoc},
     volume = {112},
     year = {1969},
     zbl = {0183.25101},
     url = {http://geodesic.mathdoc.fr/item/MZ_1969__112_171228/}
}