@Unpublished{     Charts,
  Author        = "Harel, David and Thiagarajan, P.S.",
  date-added    = "2012-05-03 20:52:48 +0200",
  date-modified = "2012-05-03 20:54:35 +0200",
  Keywords      = "message sequence charts",
  Title         = "Message Sequence Charts",
  Year          = "2008",
  File          = "Message Sequence Charts - Harel, Thiagarajan (0) (0) - a - a - n.pdf"
}

@Unpublished{ Charts, Author = "Harel, David and Thiagarajan, P.S.", date-added = "2012-05-03 20:52:48 +0200", date-modified = "2012-05-03 20:54:35 +0200", Keywords = "message sequence charts", Title = "Message Sequence Charts", Year = "2008", File = "Message Sequence Charts - Harel, Thiagarajan (0) (0) - a - a - n.pdf" }