@article{GDZPPN002026368,
title = {View-Obstruction Problems. (Short Communications).},
journal = {Aequationes mathematicae},
volume = {8},
year = {1972},
pages = {197-198},
url = {http://dml.mathdoc.fr/item/GDZPPN002026368}
}
Cusick, T.W. View-Obstruction Problems. (Short Communications).. Aequationes mathematicae, Tome 8 (1972) pp. 197-198. http://gdmltest.u-ga.fr/item/GDZPPN002026368/