APA (7th ed.) Citation

Gray, J., Smith, G. W., & Mill, J. S. (1991). J.S. Mill, On liberty in focus. Routledge.

Chicago Style (17th ed.) Citation

Gray, John, G. W. Smith, and John Stuart Mill. J.S. Mill, On Liberty in Focus. London ; New York: Routledge, 1991.

MLA (9th ed.) Citation

Gray, John, et al. J.S. Mill, On Liberty in Focus. Routledge, 1991.