@InProceedings{islip1991_088,
   author      = {W. H. Mitchell and Edward A. Ashcroft},
   title       = {{Rx for Syntax: Operator Nets for Formal Visual Programming}},
   editor      = {R. Jagannathan},
   booktitle   = {{Proceedings of the 4th International Symposium on Lucid and Intensional Programming}},
   year        = {1991},
   pages       = {88--97},
   publisher   = {SRI International},
   address     = {Menlo Park, California},
   doi         = {\url{http://plaice.web.cse.unsw.edu.au/archive/islip/1991/islip1991_088.pdf}},
   note        = {Held {29--30 April 1991}},
}