APA (7th ed.) Citation

Gray, T., Mason, W., & Walpole, H. (1819). Gray's letters. Published by John Sharpe, Piccadilly.

Chicago Style (17th ed.) Citation

Gray, Thomas, William Mason, and Horace Walpole. Gray's Letters. London: Published by John Sharpe, Piccadilly, 1819.

MLA (9th ed.) Citation

Gray, Thomas, et al. Gray's Letters. Published by John Sharpe, Piccadilly, 1819.