Environmental protection

Subject Source: {:aat=>"Art & Architecture Thesaurus", :cash=>"Canadian Subject Headings", :gmgpc=>"TGM II, Genre and physical characteristic terms", :ingest=>"Unspecified ingested source", :lcgft=>"Library of Congress Genre/Form Terms", :lcsh=>"Library of Congress Subject Headings", :lcshac=>"Library of Congress Children's and Young Adults' Subject Headings", :local=>"Local sources", :mesh=>"Medical Subject Headings", :nal=>"National Agricultural Library subject authority file", :not_applicable=>"Not applicable", :not_specified=>"Source not specified", :other=>"Other", :ram=>"Répertoire d'autorités RAMEAU", :rbgenr=>"Genre Terms: A Thesaurus for Use in Rare Book and Special Collections Cataloguing", :rvm=>"Répertoire de vedettes-matière", :sears=>"Sears List of Subject Heading", :tgn=>"Getty Thesaurus of Geographic Names"}