The Collaborative International Dictionary of English v.0.48:

Referable \Ref"er*a*ble\ (r?f"?r*?*b'l), a.
   Capable of being referred, or considered in relation to
   something else; assignable; ascribable. [Written also
   referrible.]
   [1913 Webster]

         It is a question among philosophers, whether all the
         attractions which obtain between bodies are referable
         to one general cause.                    --W.
                                                  Nicholson.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Referrible \Re*fer"ri*ble\ (-r?*b'l), a.
   Referable. --Hallam.
   [1913 Webster]