A distinctive feature of the constitutional structure of the Netherlands Indies was the division between the areas directly ruled by the government in Batavia and the 'self-governing' realms that were tied to the Netherlands by treaties or contracts but retained some degree of autonomy. In a series of articles written between 1950 and 1964 G.J. Resink argues that as late as 1910 many self-governing realms in fact retained their sovereignty and had relations with the government in Batavia that were international in character. Central to his argument is the assertion that these realms had their own territorial waters, for the possession of territorial waters may be seen as one of the attributes of state sovereignty.