APA (7th ed.) Citation

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

Chicago Style (17th ed.) Citation

Johnston, Ronald John. The Challenge for Geography: A Changing World, a Changing Discipline. Oxford: Blackwell, 1993.

MLA (9th ed.) Citation

Johnston, Ronald John. The Challenge for Geography: A Changing World, a Changing Discipline. Blackwell, 1993.