@article{10_4064_cm_39_2_289_296,
     author = {Peter Wintgen},
     title = {On the total curvature of surfaces in $E^4$},
     journal = {Colloquium Mathematicum},
     pages = {289--296},
     publisher = {mathdoc},
     volume = {39},
     number = {2},
     year = {1978},
     doi = {10.4064/cm-39-2-289-296},
     language = {en},
     url = {http://geodesic.mathdoc.fr/articles/10.4064/cm-39-2-289-296/}
}