@INPROCEEDINGS{func-vis1:pengcheng-shriram,
AUTHOR = "Pengcheng Wu and Shriram Krishnamurthi and Karl Lieberherr",
TITLE = "{Traversing Recursive Object Structures: The Functional Visitor in Demeter}",
BOOKTITLE = "2003 SPLAT Workshop: Software Engineering Properties for 
Languages and Aspect Technologies ",
YEAR = "2003",
ADDRESS = "Northeastern University, Boston (AOSD 2003)",
PAGES = "",
EDITOR = "",
PUBLISHER = "",
NOTE =  "http://www.daimi.au.dk/~eernst/splat03/"
}

Paper.

Implementation.

Notes by Karl:

A better functional visitor has been introduced by Bryan Chadwick.