@article{01669225, title = {A family of conics and three special ruled surfaces.}, journal = {Beitr\"age zur Algebra und Geometrie}, volume = {42}, year = {2001}, pages = {531-545}, zbl = {0998.51014}, language = {en}, url = {http://dml.mathdoc.fr/item/01669225} }
Schröcker, Hans-Peter. A family of conics and three special ruled surfaces.. Beiträge zur Algebra und Geometrie, Tome 42 (2001) pp. 531-545. http://gdmltest.u-ga.fr/item/01669225/