As stated above, where rules governing referendums are submitted to referendum, this is due to their nature (usually constitutional) rather than their substance, except for certain constitutional rules relating to referendums. Few constitutions contain provisions relating to local or regional referendums: it is consequently fairly unusual for them to be submitted to referendum. In Armenia for instance, only the constitutional provision allowing the institution of the referendum can be amended solely by referendum, and it does not explicitly mention local referendums.