TY - JOUR T1 - Climatic Information from Ratios of Cellulose in Tree Rings JF - Nature Y1 - 1976 A1 - Gray, John A1 - Thompson, Peter KW - 18 isotope KW - cellulose KW - climate KW - environment KW - O KW - oxygen KW - paleoclimatology KW - ratios KW - tree rings VL - 262 IS - No. 5568 ER -