Universality and the challenge to the unity of international law New developments in theory Chapter 3 Sources of international law Law-making treaties and 'contract treaties' Parties to international treaties and 'internationalized contracts' Custom Where to look for evidence of customary law The pro blem of re What state The psychological element in the formation of customary law (opinio iuris) 'Instant'customary law Universality and the consensual theory of international law General principles of lw Learned writers Other possible sources of international law Acts of international organizations 'Soft law Equity The hierarchy of the sources lus cogens Obligations erga omnes and 'international crimes' Codification of international law law and municipal law Dualist and monist theories The attitude of international law to municipal law The attitude of national legal systems to international law Treaties Custom and general principles Conclusions Public international law and private international law chapter 5 states and governments State Defined terriory Population Effective control by a government 3 Universality and the challenge to the unity of international law New developments in theory Chapter 3 Sources of international law Treaties Law-making treaties and ‘contract treaties’ Parties to international treaties and ‘internationalized contracts’ Custom Where to look for evidence of customary law The problem of repetition What states say and what states do The psychological element in the formation of customary law (opinio iuris) ‘Instant’ customary law Universality and the consensual theory of international law General principles of law Judicial decisions Learned writers Other possible sources of international law Acts of international organizations ‘Soft’ law Equity The hierarchy of the sources Ius cogens Obligations erga omnes and ‘international crimes’ Codification of international law Chapter 4 International law and municipal law Dualist and monist theories The attitude of international law to municipal law The attitude of national legal systems to international law Treaties Custom and general principles Conclusions Public international law and private international law Chapter 5 States and governments States Defined territory Population Effective control by a government