Fisher, R. (1991). Heartland of a continent: America's plains and prairies. National Geographic Society.
Style de citation Chicago (17e éd.)Fisher, Ron. Heartland of a Continent: America's Plains and Prairies. Washington, D.C.: National Geographic Society, 1991.
Style de citation MLA (9e éd.)Fisher, Ron. Heartland of a Continent: America's Plains and Prairies. National Geographic Society, 1991.
Attention : ces citations peuvent ne pas être correctes à 100%.