TY - JOUR A1 - Francey, R. J. A1 - Frederiksen, J. S. A1 - Steele, L. P. A1 - Langenfelds, R. L. T1 - Variability in a four-network composite of atmospheric CO2 differences between three primary baseline sites JO - Atmos. Chem. Phys. Discuss. J1 - ACPD VL - 2019 SP - 1 EP - 26 Y1 - 2019/05/15 PB - Copernicus Publications SN - 1680-7375 UR - https://acp.copernicus.org/preprints/acp-2019-300/ L1 - https://acp.copernicus.org/preprints/acp-2019-300/acp-2019-300.pdf DO - 10.5194/acp-2019-300 ER -