@article{AM2_1973__9_136343,
     author = {T.W. CUSICK},
     title = {View-Obstruction {Problems}},
     journal = {Aequationes mathematicae},
     pages = {165--170},
     publisher = {mathdoc},
     volume = {9},
     year = {1973},
     zbl = {0265.52003},
     url = {http://geodesic.mathdoc.fr/item/AM2_1973__9_136343/}
}