this idea is not fleshed out.  what happens?

I think there's a good example now.

  --John Abbe.....Mon Jun 01 18:26:33 -0700 2009

so if there are any constraints besides refer_to, do we just not return the non-existent ones?

  --Ethan McCutchen.....Fri Jul 23 10:31:41 -0700 2010

also see track and make findable all references

  --John Abbe.....Tue Feb 08 14:41:07 -0800 2011