Não informado. (1972). Geographical survey. Ball State University, Department of Geography and Geology.
Citação do estilo Chicago (17ª ed.)Não informado. Geographical Survey. Muncie, Ind: Ball State University, Department of Geography and Geology, 1972.
Citação MLA (8ª ed.)Não informado. Geographical Survey. Ball State University, Department of Geography and Geology, 1972.
警告：這些引文格式不一定是100％准確.