EC is also often found in
European Union law, where it refers to the
Treaty Establishing the European Community as amended by the
Treaty of Amsterdam: "Article 28 EC," for instance.
However, "Article 28 EC" is not the same as "Article 28 of the EC Treaty." In fact, Article 28 EC is actually Article 30 of the EC Treaty. This is because writing out the name of the treaty indicates that the author is referring to the original treaty, which was renumbered after the Treaty of Amsterdam.
Being able to convert the old article numbers to the new article numbers can be a very useful skill in dealing with EU law.