1. Nakazawa T, Machida T, Tanaka M, Fujii Y, Aoki S, Watanabe O (1993) Atmospheric CO2 concentrations and carbon isotopic ratios for the last 250 years deduced from an Antarctic ice core, H 15. In: Proceedings of fourth international conference on analysis and evaluation of atmospheric CO2 data, present and past, pp 193–196.
http://caos.sakura.ne.jp/tgr/observation/co2
2. Morimoto S, Nakazawa T, Aoki S, Hashida G, Yamanouchi T (2003) Concentration variations of atmospheric CO2 observed at Syowa Station, Antarctica from 1984 to 2000, Tellus, 55B, pp 170–177
3. Japan Meteorological Agency,
http://ds.data.jma.go.jp/ghg/kanshi/obs/co2_monthave_ryo.html
4. IPCC Fourth Assessment Report: Climate Change 2007: Working Group I: The Physical Science Basis
5. Haywood AM, Dowsett HJ, Valdes PJ, Lunt DJ, Francis JE, Sellwood BW (2009) Introduction. Pliocene climate, processes and problems. Phil Trans R Soc A, 13 January 2009.
https://doi.org/10.1098/rsta.2008.0205