^James Hoggan, Richard Littlemore. Climate Cover-Up: The Crusade to Deny Global Warming. Greystone Books Ltd. 2009: 79 [November 1, 2020]. ISBN 978-1553654858. (原始内容存档于October 1, 2024). Similarly, the Heartland Institute, a small regional think tank in the 1990s, emerged as a leading force in climate change denial in the past decade