@inproceedings{grps2008-99,
author = "Eliseo Marzal, Laura Sebastia, Eva Onaindia",
title = "Detection of unsolvable temporal planning problems through the use of landmarks",
booktitle = "18th European Conference on Artificial Intelligence (ECAI'08)",
publisher = "IOS Press",
pages = "919-920",
isbn = "978-1-58603-891-5",
year = "2008"
}