Não informado. (1926). Illinois Petroleum. Illinois State Geological Survey.
Style de citation Chicago (17e éd.)Não informado. Illinois Petroleum. Urbana, Ill: Illinois State Geological Survey, 1926.
Style de citation MLA (8e éd.)Não informado. Illinois Petroleum. Illinois State Geological Survey, 1926.
Attention : ces citations peuvent ne pas être correctes à 100%.