How International Law Texts are Created

The ICJ statute shows that International Law does not have an easily identifiable "law-giver". Under these circumstances, how do we find out if something is a rule in international law? What is it we are looking for? The ways norms are identified as international "law" include: agreements negotiated by the affected parties, deference to a third-party decision-maker, academic persuasion and consensus, and custom (state practice and the opinion that the practice is dictated by a legal obligation).
It is important to remember that there are two allied meanings of the word "source". One sense is related to the origins of the relevant, substantive norms and principles. The other sense is grounded in identifying the actual texts involved in the process