In the international labour movement, the freedom of association is a right identified under international labour standards as the right of workers to organize and collectively bargain. Freedom of association, in this sense, is recognized as a fundamental human right by a number of documents including the Universal Declaration of Human Rights and International Labour Organization Convention C87 and Convention C98 – two of the eight fundamental, core international labour standards. 'Freedom of association' can also refer to legal bans on private contracts negotiated between a private employer and their employees requiring workers at a particular workplace to join a union as a term and condition of employment. Supporters of this sort of private freedom of association claim that the right to join a union incorporates a right not to join a union. In the United States, the term 'right to work' is more common for this type of law.