"Patents." . . "Patents United States Handbooks, manuals, etc." . . "United States. Patent and Trademark Office." . . "United States. Patent Office." . . "Periodicals"@en . . . . "General information concerning patents"@en . . . . . . . . . . . . . . . . "Handbooks and manuals"@en . . "Basic facts about patents"@en . . . . "United States." . . . . "Patents United States." . .