The Classification of Patents
United States. Patent Office
The Classification of Patents [electronic resource] / United States. Patent Office - Project Gutenberg, 2007 - Project Gutenberg 22685 .
Public domain in the USA.
Electronic text
Patents -- United States
T
The Classification of Patents [electronic resource] / United States. Patent Office - Project Gutenberg, 2007 - Project Gutenberg 22685 .
Public domain in the USA.
Electronic text
Patents -- United States
T