@Article{         Popova,
  Author        = "Popova, Louchka",
  date-added    = "2012-12-29 13:20:24 +0000",
  date-modified = "2012-12-29 13:21:20 +0000",
  Journal       = "Journal of Information Processing and Cybernetics",
  Keywords      = "timed Petri nets",
  Pages         = "227--244",
  Title         = "On Time Petri Nets",
  Volume        = "4",
  Year          = "1991",
  File          = "On Time Petri Nets - Popova (0) (0) - a - a - f.pdf"
}

@Article{ Popova, Author = "Popova, Louchka", date-added = "2012-12-29 13:20:24 +0000", date-modified = "2012-12-29 13:21:20 +0000", Journal = "Journal of Information Processing and Cybernetics", Keywords = "timed Petri nets", Pages = "227--244", Title = "On Time Petri Nets", Volume = "4", Year = "1991", File = "On Time Petri Nets - Popova (0) (0) - a - a - f.pdf" }