TY  - JOUR
AU  - L. M. Lerman
AU  - Ya. L. Umanskii
TI  - Classification of four-dimensional integrable Hamiltonian systems and Poisson actions of 

JO  - Sbornik. Mathematics
PY  - 1994
SP  - 479
EP  - 506
VL  - 78
IS  - 2
PB  - mathdoc
UR  - http://geodesic.mathdoc.fr/item/SM_1994_78_2_a12/
LA  - en
ID  - SM_1994_78_2_a12
ER  -