APA (7th ed.) Citation

Willis, G. P., & O'Connor, M. P. (1958). It began in Singapore. Robert Hale.

Chicago Style (17th ed.) Citation

Willis, G. P., and Michael P. O'Connor. It Began in Singapore. London: Robert Hale, 1958.

MLA (8th ed.) Citation

Willis, G. P., and Michael P. O'Connor. It Began in Singapore. Robert Hale, 1958.