| 其他書名 | A Series of Projects on Outdoor Recreation and the Conservation of Forest Life Developed Through a Study of State Parks and Forests for Elementary Schools |
| 出版 | U.S. Government Printing Office, 1927 |
| URL | http://books.google.com.hk/books?id=yty_0AEACAAJ&hl=&source=gbs_api |