APA (7th ed.) Citation

Collins. (1993). Collins gem dictionary of English spelling. HarperCollins.

Chicago Style (17th ed.) Citation

Collins. Collins Gem Dictionary of English Spelling. Glasgow: HarperCollins, 1993.

MLA (9th ed.) Citation

Collins. Collins Gem Dictionary of English Spelling. HarperCollins, 1993.

Warning: These citations may not always be 100% accurate.