Stefanos A. Nikolidakis Emmanouil Georgakakis Vasileios Giotsas Dimitrios D. Vergados Christos Douligeris A secure ubiquitous healthcare system based on IMS and the HL7 standards. 2010 PETRA http://doi.acm.org/10.1145/1839294.1839345 conf/petra/2010 db/conf/petra/petra2010.html#NikolidakisGGVD10