Create thesaurus_for_graphic_materials_genre_format.txt

Le thesaurus de classement de matériel graphique de la Bibliothèque du Congrès Américain.

The Thesaurus for Graphic Materials is a tool for indexing visual materials by subject and by genre/format. The thesaurus includes more than 7,000 subject terms and 650 genre/format terms to index types of photographs, prints, design drawings, ephemera, and other pictures.