U.S. Department of Commerce, Patent Office
技報堂
1961.3-1962.8
Classification of U.S. patents / U.S. Department of Commerce, Patent Office
v. 1 : class 1-29 , v. 2 : class 30-61 , v. 3 : class 62-93 , v. 4 : class 94-120 , v. 5 : class 121-148 , v. 6 : class 149-188 , v. 7 : class 189-219 , v. 8 : class 220-251 , v. 9 : class 252-284 , v. 10 : class 285-346
Available at 3 libraries
