Ludwig, G. H. (2011). Opening space research: Dreams, technology, and scientific discovery. American Geophysical Union.
Chicago-referens (17:e uppl.)Ludwig, George H. Opening Space Research: Dreams, Technology, and Scientific Discovery. Washington, DC: American Geophysical Union, 2011.
MLA-referens (9:e uppl.)Ludwig, George H. Opening Space Research: Dreams, Technology, and Scientific Discovery. American Geophysical Union, 2011.
Varning: dessa hänvisningar är inte alltid fullständigt riktiga.