| 其他書名 | Proceedings of a Round Table Conference, Columbus, Ohio, October 15, 1929 |
| 出版 | Agricultural Service Department, Chamber of Commerce of the United States, 1929 |
| URL | http://books.google.com.hk/books?id=IRMH0H7xWy0C&hl=&source=gbs_api |
| EBook | FULL_PUBLIC_DOMAIN |