Right Kan Extensions

Category Theory List, I have a number of useful references about computing left Kan Extensions, does anyone have references on computing right Kan Extensions? Is this a reasonably trivial change to the left Kan Ext. algorithms, or is there some difference, and has this been studied? Thanks, -- Robert Byrne Dept. of Computer Science Trinity College, University of Dublin Dublin 2, Ireland 16-Mar-2002 18:41:05 -0400,5660;000000000001-00000000