MLA

Webb, Sidney, and Beatrice Webb. The Decay of Capitalist Civilasation. Second edition London: George Allen & Unwin, 1923.

APA

Webb, S., & Webb, B. (1923). The decay of capitalist civilasation. Second edition London: George Allen & Unwin.

Chicago

Webb, Sidney, and Beatrice Webb. The Decay of Capitalist Civilasation. Second edition London: George Allen & Unwin, 1923.