TY  - SER
ED  -  United States. Patent Office
TI  -  The Classification of Patents 
AV  - T 
PY  - 2007///
PB  -  Project Gutenberg, 
KW  -  Patents -- United States
N1  -  Public domain in the USA;  Text
UR  -  http://www.gutenberg.org/ebooks/22685
ER  -