![[William Wheeler Hubbell, authorized to apply for patents.]](https://covers.openlibrary.org/b/id/10200621-M.jpg)
United States. Congress. Senate. Committee on Patents
Kokuritsu Kokkai Toshokan (Japan)
United States. Bureau of the Census
International Labour Office
United States. Bureau of Labor Statistics.
Sichuan Sheng di fang zhi bian zuan wei yuan hui
