External threats to our National Parks: An argument for substantive protection Author Lockhart W. Journal/Series Stanford Environmental Law Journal | Vol. 16(1); 3 - 73; 71 p. Date 1997 Source IUCN (ID: ANA-060446) Publisher | Place of publication Stanford University School of Law | Stanford, CA, USA Language English Country/Territory United States of America Subject Wild species & ecosystems Keyword National parks Protected area