@Article{BasagniBR97,
  AUTHOR	= {Basagni, S. and Bruschi, D. and Ravasio, F.},
  TITLE		= {On the Difficulty of Finding Paths of Length $k$ in
		  Digraphs},
  JOURNAL	= {Theoretical Informatics and Applications},
  VOLUME	= {31},
  NUMBER	= {5},
  PAGES		= {429--435},
  MONTH		= {September},
  YEAR		= {1997},
}