@Article{Kahl-1999b,
  author = 	 {Wolfram Kahl},
  title = 	 {Explicit Graphs and Computer Aided Notation},
  journal = 	 {Semiotica},
  year = 	 {1999},
  volume = 	 {125},
  number = 	 {1/3},
  pages = 	 {143--154},
  abstract = {In many cases, linear notation systems can be seen to encode
              underlying, \emph{implicit} graphs.
              This paper focusses on the way that
              making these graphs \emph{explicit}
              is useful for human understanding,
              and on the use of computers
              to make handling of notations based on explicit graphs
              feasible, efficient and productive.}
}