Papers related to the visitor pattern

Acyclic Visitor
acyclic-visitor-martin.ps
  avoiding dependency
  Can the same be achieved in AP without multiple inheritance
  and dynamic casting?

Interface Extension
extension-objects-gamma.ps
  seems useful for implementing Adaptive Visitor?

Propagators
propagator-tichy-feiler.ps
  seems to benefit traversal specifications to define the
  propagations?
  
Visitor Variations
variations-visitor-nordberg.ps
  what are similar tradeoffs in AP?