@InProceedings{vdH:ivt,
  author = 	 {J. van der Hoeven},
  title = 	 {A differential intermediate value theorem},
  booktitle =    {Differential equations and the {Stokes} phenomenon},
  year = 	 {2002},
  editor = 	 {B. L. J. Braaksma and G. K. Immink and
                  M. van der Put and J. Top},
  publisher =    {World Scientific},
  pages = 	 {147--170}
}