@inproceedings{grps2000-63,

   author = "J. Porteous, L. Sebastia",

   title = "Extracting and ordering landmarks for planning",

   booktitle = "Workshop of the UK Planning and Scheduling Special Interest Group (PLANSIG'00)",

   pages = "161-174",

   issn = "1368-5708",

   year = "2000"

}