TY  - JOUR
AU  - Rainer Walden
TI  - Closed surfaces in four-spaces with non-vanishing normal curvature
JO  - Colloquium Mathematicum
PY  - 1982
SP  - 257
EP  - 262
VL  - 46
IS  - 2
PB  - mathdoc
UR  - http://geodesic.mathdoc.fr/articles/10.4064/cm-46-2-257-262/
DO  - 10.4064/cm-46-2-257-262
LA  - en
ID  - 10_4064_cm_46_2_257_262
ER  -