@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/