@article{01266859,
title = {The },
journal = {Bulletin of the Belgian Mathematical Society - Simon Stevin},
volume = {4},
year = {1997},
pages = {539-548},
zbl = {0929.14027},
language = {en},
url = {http://dml.mathdoc.fr/item/01266859}
}
Van Steen, G. The . Bulletin of the Belgian Mathematical Society - Simon Stevin, Tome 4 (1997) pp. 539-548. http://gdmltest.u-ga.fr/item/01266859/