TY  - JOUR
AU  - Luis Montejano
TI  - About a problem of Ulam concerning flat sections of manifolds.
JO  - Commentarii mathematici Helvetici
PY  - 1990
SP  - 462
EP  - 473
VL  - 65
IS  - 3
PB  - mathdoc
UR  - http://geodesic.mathdoc.fr/item/CMH_1990__65_3_140207/
ID  - CMH_1990__65_3_140207
ER  -