APA (7th ed.) Citation

Butler, R., & Kerr, E. (1962). An introduction to numerical methods. London.

Chicago Style (17th ed.) Citation

Butler, R., and E. Kerr. An Introduction to Numerical Methods. London: London, 1962.

MLA (9th ed.) Citation

Butler, R., and E. Kerr. An Introduction to Numerical Methods. London, 1962.