Lambertsen, Christian J. (1971). "Carbon Dioxide Tolerance and Toxicity". Environmental Biomedical Stress Data Center, Institute for Environmental Medicine, University of Pennsylvania Medical Center. Philadelphia, PA. IFEM Report No. 2–71. Diarsipkan dari versi asli tanggal 2011-07-24. Diakses tanggal 2008-06-10.
Glatte Jr H. A.; Motsay G. J.; Welch B. E. (1967). "Carbon Dioxide Tolerance Studies". Brooks AFB, TX School of Aerospace Medicine Technical Report. SAM-TR-67-77. Diarsipkan dari versi asli tanggal 2008-05-09. Diakses tanggal 2008-06-10.
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Lambertsen, Christian J. (1971). "Carbon Dioxide Tolerance and Toxicity". Environmental Biomedical Stress Data Center, Institute for Environmental Medicine, University of Pennsylvania Medical Center. Philadelphia, PA. IFEM Report No. 2–71. Diarsipkan dari versi asli tanggal 2011-07-24. Diakses tanggal 2008-06-10.
Glatte Jr H. A.; Motsay G. J.; Welch B. E. (1967). "Carbon Dioxide Tolerance Studies". Brooks AFB, TX School of Aerospace Medicine Technical Report. SAM-TR-67-77. Diarsipkan dari versi asli tanggal 2008-05-09. Diakses tanggal 2008-06-10.