APA (7th ed.) Citation

Robertson, J. M. (1919). The problem of "Hamlet" (1. publ.). Allen & Unwin.

Chicago Style (17th ed.) Citation

Robertson, John M. The Problem of "Hamlet". 1. publ. London: Allen & Unwin, 1919.

MLA (9th ed.) Citation

Robertson, John M. The Problem of "Hamlet". 1. publ. Allen & Unwin, 1919.