The effects of international law on the domestic legal order of the various countries of the world are manifold and so are the issues covered in this bibliography. In some countries, some international treaties or treaty provisions can be invoked before and applied by national judges. These are the so-called self-executing treaties or treaty provisions. Whether treaties are self-executing is a domestic legal question for national judges to decide on an ad hoc basis. In other countries, no treaty can be applied by a national judge unless it has been transformed into national legislation by an act of the national legislature. The concept of self-executing treaties has much less significance in these countries. This difference relates to two theories of international law known as monism and dualism. Under these theories, the international and domestic legal order are considered as one indivisible hierarchy or as two separate hierarchies respectively.