1. The ORKA Project Homepage, http://www.orka-projekt.de/index-en.htm
2. Alm, C.: An Extensible Framework for Specifying and Reasoning About Complex Role-Based Access Control Models. Technical Report MIP-0901, Department of Informatics and Mathematics. University of Passau, Germany (2009)
3. Alm, C., Drouineaud, M.: Analysis of Existing Policy Languages. Technical report, ORKA Consortium (2007), http://www.orka-projekt.de/download/del-ap2.3-requirements-policy-language.pdf
4. Alm, C., Drouineaud, M., Faltin, U., Sohr, K., Wolf, R.: On Classifying Authorization Constraints Approaches. Technical report, ORKA Consortium (2006), http://www.orka-projekt.de/download/del-ap2.1-authorization-constraints.pdf
5. Alm, C., Wolf, R.: The Definition of the OPL Access Control Policy Language. Technical Report MIP-0902, Department of Informatics and Mathematics. University of Passau, Germany (2009)