TY  - JOUR
AU  - S. A. Popov
TI  - Knotting of contractible two-dimensional polyhedra in~$\mathbf R^4$
JO  - Sbornik. Mathematics
PY  - 1972
SP  - 333
EP  - 341
VL  - 18
IS  - 2
PB  - mathdoc
UR  - http://geodesic.mathdoc.fr/item/SM_1972_18_2_a11/
LA  - en
ID  - SM_1972_18_2_a11
ER  -