Stefano Bistarelli Fabio Martinelli Francesco Santini A Semantic Foundation for Trust Management Languages with Weights: An Application to the RTFamily. 481-495 2008 ATC http://dx.doi.org/10.1007/978-3-540-69295-9_38 conf/atc/2008 db/conf/atc/atc2008.html#BistarelliMS08