Publications

List of our publications on DBLP

Local list of our publications

Books and book chapters

 

 Creating Personal, Social, and Urban Awareness through Pervasive Computing, B. Guo, D. Riboni, P. Hu (Eds.), IGI Global, 2013. ISBN: 978-1-4666-4697-1. (IGI Global Access) Image  Privacy in Location-Based Applications: Research Issues and Emerging Trends, C. Bettini, S. Jajodia, P. Samarati, X. S. Wang (Eds.), State of the Art Survey, LNCS vol. 5599, Springer, 2009. (Springer Access)
Bonchi-Ferrari-Book  C. Bettini, S. Mascetti, D. Freni, X. S. Wang, S. Jajodia  Privacy and anonymity in location data management. In Privacy-Aware Knowledge Discovery: Novel Applications and New Techniques, Chapman & Hall/CRC Press, 2010. Image  C. Bettini, X.S. Wang, S. Jajodia. Temporal Granularity. In Encyclopedia of Database Systems, Liu, Ling; Özsu, M. Tamer (Eds.), Springer, 2009. ISBN: 978-0-387-49616-0. (Springer Access)
Image  C. Bettini, S. Mascetti, X.S. Wang. Privacy Protection through Anonymity in Location-based Services. In Handbook of Database Security: Applications and Trends, Gertz, Michael; Jajodia, Sushil (Eds.), Springer, 2008. ISBN:978-0-387-48532-4. (Springer access.) Image  C. Bettini, S. Mascetti, X.S. Wang. Privacy Issues in Location-based Services. In Encyclopedia of  GIS, Shekhar, Shashi; Xiong, Hui (Eds.), Springer, 2008. ISBN: 978-0-387-30858-6. (Springer access)
Image  A. Agostini, C. Bettini, D. Riboni. Integrated Profiling of Users, Terminals, and Provisioning Environments. In The Handbook of Mobile Middleware, P. Bellavista and A. Corradi (Eds.), pp. 901-937, Auerbach Publications, 2006. ISBN: 0849338336. (ACM portal link.) Image  C. Bettini, S. Mascetti, V. Pupillo. A System Prototype for Solving Multi-Granularity Temporal CSP, In Recent Advances in Constraints, B. Faltings, A. Petcu, F. Rossi, F. Fages (Eds.), Revised selected papers from CSCLP 2004, LNAI 3419, pp.142-156, Springer, 2005. ISBN: 978-3-540-25176-7. (Springer Access)

Journal papers

  • Claudio Bettini, Daniele Riboni, "Incremental Release of Differentially-Private Check-in Data". Journal of Pervasive and Mobile Computing, Vol. 16 Part B:220-238. Springer, 2015. (DOI: 10.1016/j.pmcj.2014.11.007).
  • Claudio Bettini, Daniele Riboni, "Privacy Protection in Pervasive Systems: State of the Art and Technical Challenges". Journal of Pervasive and Mobile Computing, Vol. 17 Part B:159-174. Springer, 2015. (DOI: 10.1016/j.pmcj.2014.09.010).
  • Daniele Riboni, Antonio Villani, Domenico Vitali, Claudio Bettini, Luigi V. Mancini, "Obfuscation of Sensitive Data for Incremental Release of Network Flows". IEEE/ACM Transactions on Networking, 23(2):672-686, IEEE Computer Society, 2015. (DOI: 10.1109/TNET.2014.2309011).
  • Daniele Riboni, Claudio Bettini, "Context Provenance to Enhance the Dependability of Ambient Intelligence Systems". Personal and Ubiquitous Computing, special issue on Sensor-driven Computing and Applications for Ambient Intelligence, 16(7):799-818. Springer, 2012. (DOI: 10.1007/s00779-011-0448-3).
  • Daniele Riboni, Linda Pareschi, Claudio Bettini, "JS-Reduce: Defending Your Data from Sequential Background Knowledge Attacks. IEEE Transactions on Dependable and Secure Computing, 9(3): 387 - 400, IEEE Computer Society, 2012. (DOI: 10.1109/TDSC.2012.19).
  • Carmen Ruiz Vicente, Dario Freni, Claudio Bettini, Christian S. Jensen.Location-Related Privacy in Geo-Social Networks. IEEE Internet Computing, 15(3):20-27, 2011. (DOI: 10.1109/MIC.2011.29).
  • Sergio Mascetti, Dario Freni, Claudio Bettini, X. Sean Wang, Sushil Jajodia. Privacy in geo-social networks: proximity notification with untrusted service providers and curious buddies, The VLDB Journal, Springer, 2010. (DOI: 10.1007/s00778-010-0213-7).
  • Daniele Riboni, Claudio Bettini. OWL 2 Modeling and Reasoning with Complex Human Activities. Journal of Pervasive and Mobile Computing, special issue on Knowledge-driven activity recognition, 7(3): 379-395, Elsevier, 2011. (DOI: 10.1016/j.pmcj.2011.02.001).
  • D. Riboni, C. Bettini, "COSAR: Hybrid Reasoning for Context-aware Activity Recognition". Personal and Ubiquitous Computing, special issue on Context-aware Middleware and Applications, 15(3):271-289, Springer, 2011. (DOI: 10.1007/s00779-010-0331-7).
  • C. Bettini, O. Brdiczka, K. Henricksen, J. Indulska, D. Nicklas, A. Ranganathan, D. Riboni. A Survey of Context Modelling and Reasoning Techniques. Journal of Pervasive and Mobile Computing, 6(2):161-180, Elsevier, 2010. (DOI: 10.1016/j.pmcj.2009.06.002).
  • D. Malandrino, F. Mazzoni, D. Riboni, C. Bettini, M. Colajanni, V. Scarano. MIMOSA: Context-aware Adaptation for Ubiquitous Web Access. Personal and Ubiquitous Computing, 14(4):301-320, Springer, 2010. (DOI: 10.1007/s00779-009-0232-9).
  • A. Agostini, C. Bettini, D. Riboni. Hybrid Reasoning in the CARE Middleware for Context-Awareness, International Journal of Web Engineering and Technology, 5(1):3-23,Inderscience publishers, 2009. (DOI: 10.1504/IJWET.2009.025011 ).
  • D. Riboni, L. Pareschi, C. Bettini. Shadow Attacks on Users' Anonymity in Pervasive Computing Environments, Journal of Pervasive and Mobile Computing,  4(6):819-835, Elsevier, 2008. (DOI: 10.1016/j.pmcj.2008.04.008).
  • C. Bettini, L. Pareschi, D. Riboni. Efficient Profile Aggregation and Policy Evaluation in a Middleware for Adaptive Mobile Applications, Journal of Pervasive and Mobile Computing, 4(5):697-718, Elsevier, 2008. (DOI: 10.1016/j.pmcj.2008.04.002).
  • Sergio Mascetti, Claudio Bettini, Dario Freni, X. Sean Wang. Spatial Generalization Algorithms for LBS Privacy Preservation, Journal of Location Based Services, 1(3):179-207,Taylor & Francis, 2007. (DOI: 10.1080/17489720801941789) (pdf)
  • Chao Yao, Lingyu Wang, X. Sean Wang, Claudio Bettini, Sushil Jajodia. Evaluating privacy threats in released database views by symmetric indistinguishability, Journal of Computer Security, 17(1):5-42, IOS Press, 2009. (DOI: 10.3233/JCS-2009-0317 ).
  • Linda Pareschi, Daniele Riboni, "Preserving Anonymity in Pervasive Environments". IEEE Pervasive Computing, special Issue on Security and Privacy in Pervasive Computing - Works in Progress Section, 6(4):74-75, IEEE Computer Society, 2007. (DOI: 10.1109/MPRV.2007.86).
  • Claudio Bettini, Dario Maggiorini, Daniele Riboni, "Distributed Context Monitoring for the Adaptation of Continuous Services". World Wide Web Journal, special issue on Multi-channel adaptive information systems on the World Wide Web, 10(4):503-528, Springer, 2007. (DOI: 10.1007/s11280-007-0028-7). PDF
  • C. Bettini, S. Mascetti, X.S. Wang. Supporting temporal reasoning by mapping calendar expressions to minimal periodic sets, Journal of Artificial Intelligence Research, Volume 28, pages 299-348, AAAI Press, 2007. (JAIR access).
  • C. Bettini, X. S. Wang, S. Jajodia. Information Release Control: a Learning-based Architecture, Journal on Data Semantics II, LNCS 3360, pp. 176-198, Springer-Verlag, Berlin Heidelberg, 2005. ISBN: 3-540-24208-2. (Springer access). !- and local pdf)-->
  • C. Bettini, S. Jajodia, X. S. Wang, D. Wijesekera. Reasoning with advanced policy rules and its application to access control Journal of Digital Libraries, 4(3): 156-170, Springer-Verlag, Berlin Heidelberg, 2004. ISSN: 1432-5012. (Springer access). !- and local pdf).-->
  • Claudio Bettini, Simone Ruffini, Direct Granularity Conversions among Temporal Constraints, Journal of Universal Computer Science, 9(9):1123--1136, Springer, 2003. (JUCS access). !- and local pdf).-->
  • Claudio Bettini, Angelo Montanari, Temporal representation and reasoning, Data & Knowledge Engineering, 44(2): 139-141, Elsevier, 2003. (pdf).
  • C. Bettini, S. Jajodia, X. S. Wang, D. Wijesekera. Provisions and Obligations in Policy Rule Management Journal of Network and Systems Management, 11(3): 351-372, Kluwer Academic Publishers, 2003. (pdf).

Edited volumes

  • Special issue on Temporal Representation and Reasoning, Data & Knowledge Engineering Journal, Edited by Claudio Bettini and Angelo Montanari. Elsevier Science, 44(2), 2003.

Refereed Conference and Workshop papers

  • Daniele Riboni, Claudio Bettini, Gabriele Civitarese, Zaffar Haider Janjua, Rim Helaoui, "Fine-grained Recognition of Abnormal Behaviors for Early Detection of Mild Cognitive Impairment". In Proceedings of the 2015 IEEE International Conference on Pervasive Computing and Communications (PerCom), pp. 149-154, IEEE Computer Society, 2015. PDF
  • Daniele Riboni, Claudio Bettini, Gabriele Civitarese, Zaffar Haider Janjua, Viola Bulgari, "From Lab to Life: Fine-grained Behavior Monitoring in the Elderly's Home". In Proceedings of the 2015 IEEE International Conference on Pervasive Computing and Communications Workshops, pp. 344-349. IEEE Computer Society, 2015. PDF
  • Gabriele Civitarese, Zaffar Haider Janjua, Daniele Riboni, Claudio Bettini, "Demonstration of the FABER System for Fine-grained Recognition of Abnormal Behaviors". In Proceedings of the 2015 IEEE International Conference on Pervasive Computing and Communications Workshops, pp. 199-201. IEEE Computer Society, 2015. PDF
  • Andrea Gerino, Nicolò Alabastro, Cristian Bernareggi, Dragan Ahmetovic, Sergio Mascetti, "MathMelodies: inclusive design of a didactic game to practice Mathematics". In proceedings of the 14th International Conference on Computers Helping People with Special Needs (ICCHP). Springer, to appear.
  • Marzia Taibbi, Cristian Bernareggi, Andrea Gerino, Dragan Ahmetovic, Sergio Mascetti. "AudioFunctions: Eyes-free Exploration of Mathematical Functions on Tablets". In proceedings of the 14th International Conference on Computers Helping People with Special Needs (ICCHP). Springer, to appear.
  • Daniele Riboni, Claudio Bettini, "Differentially-Private Release of Check-in Data for Venue Recommendation". In Proceedings of the 2014 IEEE International Conference on Pervasive Computing and Communications (PerCom), pp. 190-198, IEEE Computer Society, 2014. (pdf)
  • Rim Helaoui, Daniele Riboni, Heiner Stuckenschmidt, "A Probabilistic Ontological Framework for the Recognition of Multilevel Human Activities". In Proceedings of the 2013 ACM International Joint Conference on Pervasive and Ubiquitous Computing (UbiComp), pp. 345-354, ACM, 2013. (pdf)
  • Daniele Riboni, Antonio Villani, Domenico Vitali, Claudio Bettini, Luigi V. Mancini, "Obfuscation of Sensitive Data in Network Flows". In Proceedings of the 31th IEEE International Conference on Computer Communications (INFOCOM), pp. 2372-2380, 2012. (pdf)
  • Rim Helaoui, Daniele Riboni, Mathias Niepert, Claudio Bettini, Heiner Stuckenschmidt, "Towards Activity Recognition using Probabilistic Description Logics". In Activity Context Representation: Techniques and Languages, AAAI Technical Report WS-12-05, pp. 26-31. AAAI, 2012. (pdf)
  • Daniele Riboni, Claudio Bettini, "Private Context-aware Recommendation of Points of Interest: An Initial Investigation". In Proceedings of CoMoRea'12, 9th IEEE Workshop on Context Modeling and Reasoning, pp. 584-589. IEEE Computer Society, 2012. (pdf)
  • Daniele Riboni, Claudio Bettini, "Integrating Identity, Location, and Absence Privacy in Context-aware Retrieval of Points of Interest". In Proceedings of the 12th International Conference on Mobile Data Management (MDM'11), IEEE Computer Society, 2011. (pfd)
  • Daniele Riboni, Linda Pareschi, Laura Radaelli, Claudio Bettini, "Is Ontology-based Activity Recognition Really Effective?". Proceedings of CoMoRea'11, 8th IEEE Workshop on Context Modeling and Reasoning. IEEE Computer Society, 2011. (pdf)
  • Dario Freni, Carmen Ruiz Vicente, Sergio Mascetti, Claudio Bettini, Christian S. Jensen. "Preserving Location and Absence Privacy in Geo-Social Networks". Proc. of 19th ACM International Conference on Information and Knowledge Management (CIKM ‘10), ACM, 2010. (DOI: 10.1145/1871437.1871480)
  • Daniele Riboni, Linda Pareschi, Claudio Bettini, "Towards the Adaptive Integration of Multiple Context Reasoners in Pervasive Computing Environments". In Proceedings of CoMoRea'10, 7th IEEE Workshop on Context Modeling and Reasoning, pp. 25-29. IEEE Computer Society, 2010. (pdf)
  • S. Mascetti, C. Bettini, D. Freni. Longitude: Centralized Secure Computation of Users' Proximity. Proc. of  6th VLDB workshop on Secure Data Management (SDM '09), LNCS 5776, Springer, 2009. (pdf)
  • D. Riboni, L. Pareschi, C. Bettini, S. Jajodia. Preserving Anonymity of Recurrent Location-based Queries. 16th International Symposium on Temporal Representation and Reasoning (TIME-2009), IEEE Computer Society, 2009. (pdf)
  • D. Riboni, C. Bettini. Context-aware Activity Recognition through a Combination of Ontological and Statistical Reasoning. 6th International Conference on Ubiquitous Intelligence and Computing (UIC-09), pp. 39-53, LNCS 5585, Springer, 2009. (pdf) --Full paper (pdf)-->
  • D. Riboni, C. Bettini. Cor-Split: Defending Privacy in Data Re-Publication from Historical Correlations and Compromised Tuples. 21st International Conference on Scientific and Statistical Database Management (SSDBM 2009), LNCS 5566, pp. 562-579, Springer, 2009. (pdf)
  • D. Riboni. Towards the Combination of Statistical and Symbolic Techniques for Activity Recognition. Extended abstract of invited talk at the 6th IEEE Workshop on Context Modeling and Reasoning (CoMoRea'09), colocated with PerCom'09, Galveston, Texas, 13 March 2009. Extended abstract (pdf). Slides (pdf)
  • D. Riboni, L. Pareschi, C. Bettini. POIsafe: a Privacy-Conscious System for Retrieval of Points of Interest. 3rd Workshop on Combining Context with Trust, Security and Privacy (EuroCAT 2009), in conjunction with EuroPKI and ISC, CEUR Workshop Proceedings, ISSN 1613-0073, 2009.
  • S. Mascetti, C. Bettini, D. Freni, X.S. Wang, S. Jajodia. Privacy-Aware Proximity Based Services. Proc. of the 10th International Conference on Mobile Data Management (MDM-2009), IEEE Computer Society, 2009.
 (PDF )
  • S. Mascetti, C. Bettini, X.S. Wang, D. Freni, S. Jajodia. ProvidentHider: an Algorithm to Preserve Historical k-Anonymity in LBS. Proc. of the 10th International Conference on Mobile Data Management (MDM-2009), IEEE Computer Society, 2009. (PDF )
  • D. Riboni, L. Pareschi, C. Bettini, Privacy in Georeferenced Context-aware Services: A Survey. First International Workshop on Privacy in Location-Based Applications (PiLBA '08), October 9, 2008 - Malaga, Spain. In conjunction with the 13th European Symposium on Research in Computer Security. CEUR Workshop Proceedings vol-397.
  • L. Pareschi, D. Riboni, C. Bettini. Protecting Users' Anonymity in Pervasive Computing Environments. In Proc. of the Sixth IEEE International Conference on Pervasive Computing and Communications (PERCOM 2008), IEEE Computer Society. (pdf)
  • L. Pareschi, D. Riboni, A. Agostini, C. Bettini. Composition and Generalization of Context Data for Privacy Preservation. In Proc. of the 5th Workshop on Context Modeling and Reasoning (CoMoRea 2008), IEEE Computer Society. (pdf)
  • L. Pareschi, C. Bettini. Beyond Anonymity in Location Based Services in Proc. of the Fifteenth Italian Symposium on Advanced Database Systems (SEBD 2007), ISBN: 978-88-902981-0-3, 2007.
  • S. Mascetti, C. Bettini. A Comparison of Spatial Generalization Algorithms for LBS Privacy Preservation, in Proc. of the International Workshop on Privacy-Aware Location-based Mobile Services (PALMS-2007), IEEE Computer Society, 2007.
  • C. Bettini, D. Riboni. Context-aware Web Services for Distributed Retrieval of Points of Interest. In Proc. of the Second International Conference on Internet and Web Applications and Services (ICIW 2007), IEEE Computer Society, 2007. (pdf)
  • C. Bettini, S. Mascetti, X.S. Wang, S. Jajodia. Anonymity in Location-based Services: Towards a General Framework, in Proc. of the 8th International Conference on Mobile Data Management (MDM-2007), IEEE Computer Society, 2007.
  • C. Bettini, L. Pareschi, S. Jajodia. Anonymity and diversity in LBS: a preliminary investigation, in Proc. of the Fifth IEEE International Conference on Pervasive Computing and Communications (PERCOM-07), Work in progress session, pp. 577-580, IEEE Computer Society, 2007.
  • A. Agostini, C. Bettini, D. Riboni. A Performance Evaluation of Ontology-based Context Reasoning, in Proc. of the Fifth IEEE International Conference on Pervasive Computing and Communications, 4th International Workshop on Context Modeling and Reasoning, pp. 3-8, IEEE Computer Society, 2007. (pdf)
  • A. Agostini, C. Bettini, D. Riboni. Experience Report: Ontological Reasoning for Context-aware Internet Services, in Proc. of 3rd International Workshop on Context Modeling and Reasoning, pp. 8-12, IEEE Computer Society, 2006. ISBN 0-7695-2520-2. (pdf)
  • S. Mascetti, C. Bettini, X.S. Wang, S. Jajodia. k-Anonymity in Databases with Timestamped Data, in Proc. of 13th International Symposium on Temporal Representation and Reasoning, pp. 20-25, IEEE Computer Society, 2006. (pdf).
  • C. Bettini, D. Maggiorini, D. Riboni. Distributed Context Monitoring for Continuous Mobile Services, in Proc. of MOBIS 2005, IFIP TC8 Working Conference on Mobile Information Systems, Springer, 2005. (pdf)!-- ISBN 0-387-22851-9. (pdf) -->
  • C. Bettini, X. S. Wang, S. Jajodia. Protecting Privacy Against Location-based Personal Identification, in Proc. of the 2nd VLDB Workshop on Secure Data Management, W. Jonker and M. Petkovic (Eds.), LNCS 3674, pp. 185-199, Springer-Verlag Berlin Heidelberg 2005. (pdf)
  • A. Agostini, C. Bettini, D. Riboni. Loosely Coupling Ontological Reasoning with an Efficient Middleware for Context-awareness, in Proc. of MobiQuitous 2005. The Second Annual International Conference on Mobile and Ubiquitous Systems: Networking and Services, pp. 175-182, IEEE Computer Society, 2005. ISBN 0-7695-2375-7. (pdf)
  • C. Bettini, N. Cesa-Bianchi, D. Riboni. A Distributed Architecture for Management and Retrieval of Extended Points of Interest, in Proc. of the 25th IEEE International Conference on Distributed Computing Systems - (Workshop on Services and Infrastructure for the Ubiquitous and Mobile Internet), pp. 266-272, IEEE Computer Society Press, 2005. (pdf)
  • A. Agostini, C. Bettini, D. Riboni. Demo: Context-Aware Delivery of Extended Points of Interest, in Proc. of the 6th International Conference on Mobile Data Management (MDM 2005), pp. 322-323, ACM Publishing, 2005. (pdf)
  • C. Bettini, S. Mascetti. An Efficient Algorithm for Minimizing Time Granularity Periodical Representations, in Proc. of 12th International Symposium on Temporal Representation and Reasoning, pp. 20-25, IEEE Computer Society, 2005. (pdf).
  • A. Agostini, C. Bettini, N. Cesa-Bianchi, D. Maggiorini, D. Riboni, M. Ruberl, C. Sala, D. Vitali. Towards highly adaptive services for mobile computing, in Mobile Information Systems, E. Lawrence, B. Pernici, J. Krogstie, Eds., pp. 121--134, Springer, 2004. ISBN 0-387-22851-9. (pdf) !- IFIP TC8 Working Conference on Mobile Information Systems -->
  • C. Bettini, X. S. Wang, S. Jajodia. Identifying Sensitive Associations in Databases for Release Control, in Proc. of Secure Data Management: VLDB 2004 Workshop, W. Jonker and M. Petkovic (Eds.), LNCS N. 3178, pp. 187-201, Springer-Verlag Berlin Heidelberg, 2004. ISBN: 3-540-22983-3. (pdf, SpringerLink).
  • C. Bettini, S. Mascetti. Towards Minimal Periodical Representation of Calendar Expressions, in Proc. of ECAI-04 Workshop on Spatial and Temporal Reasoning, Valencia, Spain, 2004. (pdf).
  • C. Bettini, D. Riboni. Profile Aggregation and Policy Evaluation for Adaptive Internet Services in Proc. of the First Annual International Conference on Mobile and Ubiquitous Systems: Networking and Services (MobiQuitous'04), pp. 290-298, IEEE Computer Society, 2004. (pdf).
  • C. Bettini, S. Mascetti, X. Wang. Mapping Calendar Expressions into Periodical Granularities, in Proc. of 11th International Symposium on Temporal Representation and Reasoning, pp. 96-102, IEEE Computer Society, 2004. (pdf).
  • C. Bettini, X. S. Wang, S. Jajodia. A Learning-Based Approach to Information Release Control, in Integrity and Internal Control in Information Systems VI, Sushil Jajodia, Leon Strous, eds., Kluwer Academic Publishers, Boston, 2004, pages 83-105.(pdf).
  • A. Agostini, C. Bettini, N. Cesa-Bianchi, D. Maggiorini, D. Riboni. Integrated Profile Management for Mobile Computing, in Proc. of AI Moves to IA: Workshop on Artificial Intelligence, Information Access, and Mobile Computing, IJCAI Workshop, Acapulco, Mexico, 2003. (pdf)
  • C. Bettini, S. Mascetti, V. Pupillo. GSTP: A Temporal Reasoning System Supporting Multi-Granularity Temporal Constraints, in Proc. of Int. Joint Conference on Artificial Intelligence (IJCAI), (Intelligent Systems Demonstrations), pp. 1633-1634, Morgan Kaufmann, San Francisco, CA, 2003. (pdf)
  • C. Bettini. Web Services for Time Granularity Reasoning, Extended abstract of Invited Talk at TIME-ICTL 2003. In Proc. of TIME-ICTL Symposium, pp. 2-4, IEEE Computer Society, Los Alamitos, CA, 2003.

Technical Reports

  • Sergio Mascetti, Claudio Bettini, X. Sean Wang, Dario Freni, Sushil Jajodia. Preserving Anonymity in Location-based Services When Requests from the Same Issuer May Be Correlated. DICo Technical Report n. TR 23-07, University of Milan, Italy, 2007. (pdf)
  • Sergio Mascetti. Privacy Protection through Anonymity in Location-based Services. DICo Technical Report n. TR 22-07, University of Milan, Italy, 2007. (pdf)
  • C. Bettini, X. S. Wang, S. Jajodia. The Role of Quasi-identifiers in k-Anonymity Revisited, TR 11-06, DICo, University of Milan, Italy. July 2006. (pdf and ACM Corr entry)
  • C. Bettini, S. Mascetti. Minimal Periodical Representations of Calendar Expressions. DICo Technical Report n. TR 04-05, University of Milan, Italy, 2005. (pdf)