Anh-Tuan Gai Dmitry Lebedev Fabien Mathieu Fabien de Montgolfier Julien Reynier Laurent Viennot Acyclic Preference Systems in P2P Networks http://arxiv.org/abs/0704.3904 2007 CoRR abs/0704.3904 db/journals/corr/corr0704.html#abs-0704-3904 informal publication informal publication