@inproceedings{Jayez:Tovena:05,
  author	= {Jayez, Jacques and Tovena, Lucia},
  title		= {{When `Widening' is too Narrow}},
  booktitle	= {Proceedings of the Fifteenth Amsterdam Colloquium},
  pages		= {131--136},
  year		= {2005},
  address	= {Amsterdam}
}