Standard way of referencing an object by identity (for, eg, circular references)?

Question

Is there a standard way of referencing objects by identity in JSON? For example, so that graphs and other data structures with lots of (possibly circular) references can be

Answer 1

Douglas Crockford has a solution that uses JSONPath (an Xpath-like syntax for describing json paths). It seems fairly sane:

https://github.com/douglascrockford/JSON-js/blob/master/cycle.js