@article{GDZPPN002170701,
title = {Limits for double points of surfaces.},
journal = {Journal f\"ur die reine und angewandte Mathematik},
volume = {159},
year = {1928},
pages = {255-264},
zbl = {54.0696.03},
url = {http://dml.mathdoc.fr/item/GDZPPN002170701}
}
Hollcroft, Temple Rice. Limits for double points of surfaces.. Journal für die reine und angewandte Mathematik, Tome 159 (1928) pp. 255-264. http://gdmltest.u-ga.fr/item/GDZPPN002170701/