@inproceedings{BroersenTorrePRIMA2007,
  author    = {J.M. Broersen and L.W.N. van der Torre},
  title     = {Reasoning About Norms, Obligations, Time and Agents},
  booktitle = {Agent Computing and Multi-Agent Systems, 10th Pacific Rim International Conference on Multi-Agents, PRIMA 2007, Bangkok, Thailand, November 21-23, 2007, revised papers},
  editor    = {Aditya Ghose and Guido Governatori and Ramakoti Sadananda},
  series    = {Lecture Notes in Computer Science},
  volume    = {5044},
  year      = {2009},
  pages     = {171-182}
}