APA (7th ed.) Citation

Acton, J. E. E. D. A., Figgis, J. N., & Laurence, R. V. (1950). Lectures on modern history. Macmillan.

Chicago Style (17th ed.) Citation

Acton, John Emerich Edward Dalberg Acton, John Neville Figgis, and Reginald Vere Laurence. Lectures on Modern History. London: Macmillan, 1950.

MLA (9th ed.) Citation

Acton, John Emerich Edward Dalberg Acton, et al. Lectures on Modern History. Macmillan, 1950.