International tribunals and arbiters are often called upon to resolve substantial disputes over treaty interpretations. To establish the meaning in context, these judicial bodies may review the preparatory work from the negotiation and drafting of the treaty as well as the final, signed treaty itself.
If it is possible to answer this question, answer it for me (else, reply "unanswerable"): In addition to the final, signed treaty what else might arbiters review to establish the meaning of a treaty in context?
the preparatory work from the negotiation and drafting of the treaty