@article{AM2_1980__20_182392,
     author = {Murat R. Sertel and A. Van der Bellen},
     title = {Computations in choice groupoids.},
     journal = {Aequationes mathematicae},
     pages = {129--132},
     publisher = {mathdoc},
     volume = {20},
     year = {1980},
     zbl = {0436.90003},
     url = {http://geodesic.mathdoc.fr/item/AM2_1980__20_182392/}
}