| 其他書名 | A Report to the Iowa State Board of Education of a Survey Made Under the Direction of the Commissioner of Education |
| 出版 | U.S. Government Printing Office, 1916 |
| URL | http://books.google.com.hk/books?id=cPhEAQAAMAAJ&hl=&source=gbs_api |
| EBook | FULL_PUBLIC_DOMAIN |