One of the six founding states of Australia, Queensland has been a federated state subject to the Australian Constitution since 1 January 1901. It is sovereign, other than in the matters ceded in the Australian Constitution to the federal government. It is a parliamentary constitutional monarchy. The Constitution of Queensland sets out the operation of the state's government. The state's constitution contains several entrenched provisions which cannot be changed in the absence of a referendum. There is also a statutory bill of rights, the Queensland Human Rights Act (2019). Queensland's system of government is influenced by the Westminster system and Australia's federal system of government.