Twed, W. C. (1980). Recreation site planning and improvement in national forests: 1891 - 1942. US of Agriculture Forest Service.
Chicago-Zitierstil (17. Ausg.)Twed, William C. Recreation Site Planning and Improvement in National Forests: 1891 - 1942. Washington, DC: US of Agriculture Forest Service, 1980.
MLA-Zitierstil (9. Ausg.)Twed, William C. Recreation Site Planning and Improvement in National Forests: 1891 - 1942. US of Agriculture Forest Service, 1980.
Achtung: Diese Zitate sind unter Umständen nicht zu 100% korrekt.