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National Geographic Society (U.S.). Cartographic Division., John F. Shupe, Lisa R. Ritter, Andrew J. Wahll, Robert E. Pratt, و Wil Tirion. The Heavens ; Star Birth in the Orion Nebula. Washington, D.C.: The Society, 1995.

National Geographic Society (U.S.). Cartographic Division., et al. The Heavens ; Star Birth in the Orion Nebula. Washington, D.C.: The Society, 1995.