TY  - BOOK
AU  - Roussarie, F., Dumortier
AU  - Roussarie, R.
AU  - Zoladek, Sotomayor, H.
TI  - Bifurcations of planar vector fields: nilpotent singularities and abelian integrals
T2  - Lecture notes in mathematics
U1  - 512.55, 
PY  - 1991///
CY  - Berlin
PB  - Springer-Verlag
ER  -