APA-viite (7. p.)
Ludwig, G. H. (2011). Opening space research: Dreams, technology, and scientific discovery. American Geophysical Union.
Chicago-viite (17. p.)
Ludwig, George H. Opening Space Research: Dreams, Technology, and Scientific Discovery. Washington, DC: American Geophysical Union, 2011.
MLA-viite (9. p.)
Ludwig, George H. Opening Space Research: Dreams, Technology, and Scientific Discovery. American Geophysical Union, 2011.
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