Archival research

Denmark

• Rigsarkivet
• DUPI-Archive at DIIS
• Geological Museum
• Kort- og Matrikelstyrelsen
• Niels Bohr Archive
• Arne Noe-Nygaards Archive
• Henning Sørensens Archive
• Archive of the Arctic Institute
• Archive of the Geodetic Institute
• Erhvervsarkivet

USA

• National Archives and Record Administration II (College Park)
• National Academies of Science Archives
• Library of Congress
• Smithsonian Institution Archives
• Library of the US Army Corps of Engineers
• Library of the US Geological Survey
• Lamont Library
• Lyndon Baines Johnson Presidential Library
• Briscoe Center for American History
• Wittliff Collections, Texas State University
• American Heritage Center
• National Snow and Ice Data Center, University of Colorado

Belgium

• NATO Archives, Brussels.

France

• French National Archives, Fontainebleau and Paris.

Canada

• Library and Archives Canada, Ottawa.