Não informado. (2004). Environmental geology notes. Illinois State Geological Survey.
Chicagoスタイル(17版)引用形式Não informado. Environmental Geology Notes. Naperville, Ill: Illinois State Geological Survey, 2004.
MLA(8版)引用形式Não informado. Environmental Geology Notes. Illinois State Geological Survey, 2004.
警告: この引用は必ずしも正確ではありません.