McKenna, J. A., & Allen, N. (2010). Skycrane: Igor Sikorsky's last vision. American Institute of Aeronautics and Astronautics.
Chicago-čujuhus (17. p.)McKenna, John A., juo Ned Allen. Skycrane: Igor Sikorsky's Last Vision. Reston, Va.: American Institute of Aeronautics and Astronautics, 2010.
MLA-čujuhus (9. p.)McKenna, John A., juo Ned Allen. Skycrane: Igor Sikorsky's Last Vision. American Institute of Aeronautics and Astronautics, 2010.
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