The nationality of a person is that person's legal relationship with a state, for example a Swedish person's legal relationship with the kingdom of Sweden. Nationality is not identical to citizenship but in the majority of states most of the population are also citizens. Dual nationality means that the person has a legal relationship with two different states at the same time, for example the United Kingdom and the Republic of Ireland. The rights and duties of individual people and the states they belong to vary from country to country.
- Vonk, Olivier. Dual Nationality in the European Union: A Study on Changing Norms in Public and Private International Law and in the Municipal Laws of Four EU Member States. Martinus Nijhoff Publishers; 2012-03-19 [cited 17 August 2012]. ISBN 9789004227200. p. 19.
- Weis, Paul. Nationality and Statelessness in International Law. Brill; 1979 [cited 19 August 2012]. ISBN 9789028603295. pp. 29–61.