@inproceedings{SIGMOD-2011-LiuW,
	author        = "Lian Liu and Raymond Chi-Wing Wong",
	booktitle     = "{Proceedings of the 29th ACM SIGMOD International Conference on Management of Data}",
	doi           = "10.1145/1989323.1989369",
	isbn          = "978-1-4503-0661-4",
	pages         = "433--444",
	publisher     = "{ACM}",
	title         = "{Finding shortest path on land surface}",
	year          = 2011,
}