@article{10_21136_CMJ_1976_101402,
     author = {\v{S}vec, Alois},
     title = {On the existence of parallel normal vector fields of surfaces in $E^4$},
     journal = {Czechoslovak Mathematical Journal},
     pages = {297--303},
     publisher = {mathdoc},
     volume = {26},
     number = {2},
     year = {1976},
     doi = {10.21136/CMJ.1976.101402},
     mrnumber = {0405253},
     zbl = {0337.53044},
     language = {en},
     url = {http://geodesic.mathdoc.fr/articles/10.21136/CMJ.1976.101402/}
}