@inproceedings{ Preguiça.Martins-81ip-01,
        author = { N. Preguiça and J. L. Martins },
        title = { Revisiting Hierarchical Quorum Systems },
 		booktitle = {Proceedings of the 2001 21st IEEE International Conference on Distributed Computing Systems (ICDCS'01)},
        booktitle = { ICDCS '01: Proceedings of the The 21st International Conference on Distributed Computing Systems },
        publisher = { IEEE Computer Society },
 		doi = {http://doi.ieeecomputersociety.org/10.1109/ICDSC.2001.918956},
        year = { 2001 },
        pages = { 264-272 },
}