Sören Preibusch Spontaneous Privacy Policy Negotiations in Pervasive Environments. 814-823 2007 conf/otm/2007-w2 OTM Workshops (2) http://dx.doi.org/10.1007/978-3-540-76890-6_7 db/conf/otm/otm2007-w2.html#Preibusch07