@article{01973833,
title = {How round is a circle? Constructions of double and circular planar near-rings.},
journal = {Beitr\"age zur Algebra und Geometrie},
volume = {44},
year = {2003},
pages = {389-411},
zbl = {1044.16035},
language = {en},
url = {http://dml.mathdoc.fr/item/01973833}
}
Veldsman, Stefan. How round is a circle? Constructions of double and circular planar near-rings.. Beiträge zur Algebra und Geometrie, Tome 44 (2003) pp. 389-411. http://gdmltest.u-ga.fr/item/01973833/