Elizabeth Cowan Brown. The "wholly separate" truth: did the Yellowstone wolfreintroduction violate Section 10(J) of the Endangered Species Act?. Boston College
and interesting facts. History of Elk in Wisconsin. The Wisconsin Elk Reintroduction Project. [2007-06-04]. (原始内容存档于2011-06-08). Thomas, Jack Ward; Dale
ISBN 978-94-011-2868-1. doi:10.1007/978-94-011-2868-1_48 (英语). Monnie, James B. Reintroduction of the Trumpeter Swan to Its Former Prairie Breeding Range. The Journal