Roy, Donald. “Konsumgenossenschaften Im Strukturwandel: Consumer Co-Operatives in a Changing World: Comparative Studies on Structural Changes of Some Selected Consumer Cooperative Societies in Industrialized Countries”. Wirtschaft Und Gesellschaft, vol. 17, no. 1, Jan. 1991, pp. 108-11, https://journals.akwien.at/index.php/wug/article/view/2038.