A Converse to a Theorem on Normal Forms of Volume Forms with Respect to   a Hypersurface
  In this note we give a positive answer to a question asked by Y. Colin de Verdi\`ere concerning the converse of the following theorem, due to A. N. Varchenko: two germs of volume forms are equivalent with respect to diffeomorphisms preserving a germ of an isolated hypersurface singularity, if their difference is the differential of a form whose restriction on the smooth part of the hypersurface is exact. 
Konstantinos Kourliouros
math.SG