http://www.rssboard.org/rss-specification 720 XTF Search Results (docsPerPage=100;f6-subject=Helicopters -- History) https://catalog.wrhs.org/collections/search?docsPerPage%3D100;f6-subject%3DHelicopters%20--%20History Results for your query: docsPerPage=100;f6-subject=Helicopters -- History Thu, 01 Jan 1970 12:00:00 GMT The story of the helicopter. Francis, Devon, 1901-1986 https://catalog.wrhs.org/collections/view?docId=marc/skclmarc202890322046876.mrc https://catalog.wrhs.org/collections/view?docId=marc/skclmarc202890322046876.mrc Thu, 01 Jan 1970 12:00:00 GMT The miracle of the helicopter. Delear, Frank J., United Aircraft Corporation Sikorsky Aircraft Division. https://catalog.wrhs.org/collections/view?docId=marc/skclmarc202890322046876.mrc https://catalog.wrhs.org/collections/view?docId=marc/skclmarc202890322046876.mrc Thu, 01 Jan 1970 12:00:00 GMT