Periodicals>Journal Article:  Levit, Georgy S. (2000), The Biosphere and the Noosphere Theories of V. I. Vernadsky and P. Teilhard de Chardin: A Methodological Essay., International Archives on the History of Science/Archives Internationales D'Histoire des Sciences, 50 (144), 2000: p. 160–176, Retrieved on 2016-12-24

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