Refugee law encompasses both customary law, peremptory norms, and international legal instruments. The only international instruments directly applying to refugees are the 1951 United Nations Convention Relating to the Status of Refugees and the 1967 Protocol Relating to the Status of Refugees. Both the Convention and the Protocol are open to states, but each may be signed separately. 145 states have ratified the Convention, and 146 have ratified the Protocol. These instruments only apply in the countries that have ratified an instrument, and some countries have ratified these instruments subject to various reservations.