R. Pasley, P. Clough, R. Purves, and F. Twaroch. Proceedings of the 16th ACM SIGSPATIAL international conference
on Advances in geographic information systems, page 1--9. Irvine, California, ACM, (2008)
F. Twaroch, C. Jones, and A. Abdelmoty. Proceedings of the First International Workshop on Location and the Web (LocWeb 2008), page 61-64. Beijing, China, (April 2008)