The Bergdoll Boys, page 64
American Heritage Center, University of Wyoming
Yale University Library
Detroit Free Library
Library of Congress
Stadt Museum, Germany
Heidelberg University
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National Archives and Records Administration
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National Air and Space Museum
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Penn Pilot
Aero Club of Pennsylvania
Philadelphia City Archives
Temple University Urban Archives
FBI History Files
Center for Jewish History
Landesarchiv Baden-Württemberg, Germany
Newspaper Archive
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Wikipedia
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Town of Somerset, Maryland
Wiltrud Flothow, Germany
Rich Wagner
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Susannah Carroll
Philip Karl Barth
Patty Kessler
Nolan Doroski, Albany, New York Public Library
Debbie Harding
Seth Pancoast, Jr.
John Rizzo
Marple Township Historical Society
Delaware County Historical Society
Birdsboro of Yesterday
Bob McNulty, Philadelphia Stories
Canadian Pacific Railway
Hearst Corporation
Karl D. Qualls
Dickinson College
Russian Cultural Center, Washington, D.C.
The New York Times
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Life Magazine
Time Magazine
American Legion Weekly
Mercedes Benz Museum, Stuttgart
Historical American Building Survey
Fairmount Park Commission
Michael J. Seneca
Roberta E. Dell
Timothy W. Lake, The Bergdoll Boys
