@techreport{TR-DCC-95-05,
  number = {DCC-95-05},
  author = {Anido, Ricardo O. and Mendonça, Nabor C.},
  title = {Protocols for Maintaining Consistency of Replicated Data},
  month = {June},
  year = {1995}, 
  institution = {Department of Computer Science, University of Campinas},
  note = {In English, 33 pages.
    \par\selectlanguage{english}\textbf{Abstract}
      Data replication is a useful technique for improving the
      performance and availability in distributed database systems.
      Most of the protocols proposed in the literature to control the
      access to the replicated data use some form of voting for
      maintaining the data consistent, and follow a {\em pessimistic}
      approach, in the sense that they prevent possibly unsafe changes
      to the replicated data.  In this paper several of those protocols
      are described and compared.  Some {\em optimistic} protocols, and
      some protocols not based on voting are also briefly presented.
  }
}