J. Hu, W. Huang, H. Tseng, H. Lee, L. Ku, S. Lin, T. Liu, and C. Yang. Innovative Mobile and Internet Services in Ubiquitous Computing (IMIS),
2012 Sixth International Conference on, page 329 -333. (July 2012)
A. Java, X. Song, T. Finin, and B. Tseng. volume 5439 of Lecture Notes in Computer Science, page 118--138. Springer Berlin Heidelberg, Berlin, Heidelberg, (2009)