@article{GDZPPN002023482,
title = {Nearly Spherical Surfaces.},
journal = {Aequationes mathematicae},
volume = {2},
year = {1969},
pages = {186-193},
zbl = {0177.49501},
url = {http://dml.mathdoc.fr/item/GDZPPN002023482}
}
Guggenheimer, H. Nearly Spherical Surfaces.. Aequationes mathematicae, Tome 2 (1969) pp. 186-193. http://gdmltest.u-ga.fr/item/GDZPPN002023482/