@article{02096241,
title = {Ruled surfaces treated in terms of relative geometry. (Regelfl\"achen relativgeometrisch behandelt.)},
journal = {Beitr\"age zur Algebra und Geometrie},
volume = {45},
year = {2004},
pages = {209-215},
zbl = {1060.53011},
language = {en},
url = {http://dml.mathdoc.fr/item/02096241}
}
Stamou, Georg; Magkos, Athanasios. Ruled surfaces treated in terms of relative geometry. (Regelflächen relativgeometrisch behandelt.). Beiträge zur Algebra und Geometrie, Tome 45 (2004) pp. 209-215. http://gdmltest.u-ga.fr/item/02096241/