@article{DMGAA_2004_24_1_a9,
     author = {Chajda, Ivan and L\"anger, Helmut},
     title = {Orthorings},
     journal = {Discussiones Mathematicae. General Algebra and Applications},
     pages = {137--147},
     publisher = {mathdoc},
     volume = {24},
     number = {1},
     year = {2004},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/DMGAA_2004_24_1_a9/}
}