@InProceedings{	  Petersen97fct,
  author	= "Petersen, Holger",
  title		= "The Equivalence of Pebbles and Sensing Heads for Finite
		  Automata",
  year		= "1997",
  volume	= "1279",
  pages		= "400--410",
  publisher	= "Springer",
  address	= "Berlin",
  series	= "Lecture Notes in Computer Science",
  booktitle	= "Fundamentals of computation theory ({K}rak{\'o}w, 1997)",
  doi		= "10.1007/BFb0036201"
}