"1967 Gibraltar sovereignty referendum" . "first sovereignty referendum" . . "Sovereignty referendum, 1967" . "a referendum on sovereignty was held in 1967" . "1967 referendum" . "a referendum in September 1967" . . . . . "1967" . . . . "Gibraltar's 1967 referendum" . . . "Gibraltar sovereignty referendum of 1967" . "Gibraltar sovereignty referendum" . "Gibraltar referendum" . "1967 Gibraltar sovereignty referendum" . "vote" . "sovereignty referendum of 1967" . . "Gibraltar's first sovereignty referendum of 1967" . . "referendum on the colony's future" . "1967 sovereignty referendum" . . "referendum held in 1967" . "Gibraltar's first sovereignty referendum" . "1967 referendum on sovereignty" . . .