Finding boost::shared_ptr cyclic references

Question

Is there any tips/tricks for finding cyclic references of shared_ptr's?

This is an exmaple of what I'm trying to find - unfortunately I can't seem to find the loop in my code.

struct A
{
  boost::shared_ptr<C> anC;
};

struct B
{
  boost::shared_ptr<A> anA;
};

struct C
{
  boost::shared_ptr<B> anB;
};