It has often been thought that this inability to formulate reservations to treaty provisions which codify customary norms could be deduced from the International Court of Justice's judgement in the North Sea Continental Shelf cases:
117. 一般往往以为可以根据国际法院对北海大陆架案件的裁定，推理，不得对为习惯法规则编篡法律的条约条款提具保留：