Reference

Rubino M, Etheridge DM, Trudinger CM, Allison CE, Battle MO, Langenfelds RL, Steele LP, Curran M, Bender M, White JWC, Jenk TM, Blunier T & Francey RJ (2013). A revised 1000 year atmospheric δ13C-CO2 record from Law Dome and South Pole, Antarctica. Journal of Geophysical Research: Atmospheres 118(15):8482–8499.