TY  - JOUR
AU  - M.L., Polterovich, L.V. Bialy
TI  - Lagrangian singularities of invariant tori of hamiltonian systems with two degrees of freedom.
JO  - Inventiones mathematicae
PY  - 1989
SP  - 291
EP  - 304
VL  - 97
IS  - 2
PB  - mathdoc
UR  - http://geodesic.mathdoc.fr/item/IM_1989__97_2_143703/
ID  - IM_1989__97_2_143703
ER  -