Arne Hansen E. James Penick, Jr. : Progressive Politics and Conservation. The Ballinger-Pinchot Affair. Chicago and London, The University of Chicago Press, 1968. xvi, 207 s. 79 sh. ht [Internet]. 1. januar 1973 [henvist 24. november 2024];12. Tilgængelig hos: https://tidsskrift.dk/historisktidsskrift/article/view/51462