APA (7th ed.) Citation

Johnston, R. J. (1993). The Challenge for geography: A changing world, a changing discipline. Blackwell Publishers.

Chicago Style (17th ed.) Citation

Johnston, R. J. The Challenge for Geography: A Changing World, a Changing Discipline. Oxford, UK ; Cambridge, USA: Blackwell Publishers, 1993.

MLA (9th ed.) Citation

Johnston, R. J. The Challenge for Geography: A Changing World, a Changing Discipline. Blackwell Publishers, 1993.