APA (7th ed.) Citation

Walpole, H., Beckford, W., Radcliffe, A. W., Walpole, H., Beckford, W., & Radcliffe, A. W. (1959). Three eighteenth century romances. Scribner.

Chicago Style (17th ed.) Citation

Walpole, Horace, William Beckford, Anne Ward Radcliffe, Horace Walpole, William Beckford, and Anne Ward Radcliffe. Three Eighteenth Century Romances. New York: Scribner, 1959.

MLA (9th ed.) Citation

Walpole, Horace, et al. Three Eighteenth Century Romances. Scribner, 1959.