Jing Jin Gail-Joon Ahn Hongxin Hu Michael J. Covington Xinwen Zhang Patient-centric authorization framework for sharing electronic health records. 125-134 2009 SACMAT http://doi.acm.org/10.1145/1542207.1542228 conf/sacmat/2009 db/conf/sacmat/sacmat2009.html#JinAHCZ09