| 其他書名 | September 21-25, 1992, Estes Park Center, YMCA of the Rockies, Colorado |
| 出版 | Rocky Mountain Forest and Range Experiment Station, U.S. Department of Agriculture, 1993 |
| URL | http://books.google.com.hk/books?id=0XeK7Jz7_SQC&hl=&source=gbs_api |
| EBook | FULL_PUBLIC_DOMAIN |