Great Britain & Great Britain. Commonwealth Office. (1968). Treaty of Friendship Between Her Majesty the Queen in Respect of the United Kingdom of Great Britain and Northern Ireland and His Majesty the King of Tonga: Nukuʹalofa, May 30, 1968. H.M.S.O..

Great Britain and Great Britain. Commonwealth Office. Treaty of Friendship Between Her Majesty the Queen in Respect of the United Kingdom of Great Britain and Northern Ireland and His Majesty the King of Tonga: Nukuʹalofa, May 30, 1968. London: H.M.S.O., 1968.

Great Britain and Great Britain. Commonwealth Office. Treaty of Friendship Between Her Majesty the Queen in Respect of the United Kingdom of Great Britain and Northern Ireland and His Majesty the King of Tonga: Nukuʹalofa, May 30, 1968. H.M.S.O., 1968.