A double taxation problem arises when the person or corporation making the expertise or inspiration available is resident in one country and the user is resident in a second country. Each of the two countries may then claim the rights to tax the royalties and will not afford relief for tax paid in the other country. The burden of the tax paid for the privilege of using copyright, patents, designs, trade marks, secret processes and formulae, know-how and the like, may then be intolerably heavy. The use may have to be foregone in some countries or the user must accept a serious restriction on the profitability of his business. This creates a special difficulty in the case of developing countries.