%0 Generic %T Classification of Patents hearings before the United States House Committee on Patents, Subcommittee on Classification of Patents, Seventy-Sixth Congress, first session, on May 23, 1939. %U https://ezaccess.libraries.psu.edu/login?url=http://congressional.proquest.com/congcomp/getdoc?HEARING-ID=HRG-1939-PAS-0004