APA (7th ed.) Citation

Valentine, C. W. (1940). The difficult child and the problem of discipline (1. publ.). Methuen.

Chicago Style (17th ed.) Citation

Valentine, Charles W. The Difficult Child and the Problem of Discipline. 1. publ. London: Methuen, 1940.

MLA (9th ed.) Citation

Valentine, Charles W. The Difficult Child and the Problem of Discipline. 1. publ. Methuen, 1940.