@article{GDZPPN002200988,
title = {On elementary transformations of ruled surfaces.},
journal = {Journal f\"ur die reine und angewandte Mathematik},
volume = {346},
year = {1984},
pages = {32-35},
zbl = {0515.14008},
url = {http://dml.mathdoc.fr/item/GDZPPN002200988}
}
Lange, Herbert. On elementary transformations of ruled surfaces.. Journal für die reine und angewandte Mathematik, Tome 346 (1984) pp. 32-35. http://gdmltest.u-ga.fr/item/GDZPPN002200988/