@article {Katsianis2009,
	title = {Design and implementation approaches for location-based, tourism-related services},
	journal = {Handbook of Research on Geoinformatics},
	year = {2009},
	pages = {433-468},
	author = {Kakaletris, G. and Varoutas, D and Katsianis, D and Sphicopoulos, T}
}
