De effekten van protest op de gewoonterechtsvorming / Liesbeth LijnzaadLaw-making in the international community / by G.M. DanilenkoCustomary international law and treaties : a manual on the theory and practice of the interrelation of sources / Mark E. VilligerInternational customary law and codification : an examination of the continuing role of custom in the present period of codification of international law / [by] H.W.A. ThirlwayPraktijk en internationale gewoonteregelvorming / A.L. van den BerghCustomary international law and treaties : a study of their interactions and interrelations with special consideration of the 1969 Vienna convention on the law of treaties / by Mark E. Villiger