Use of carbon isotopes ('13 IND.C', '14 IND.C') in soil to evaluate vegetation changes during the holocene in central Brazil - Pessenda, Luiz Carlos Ruiz; Aravena, R; Melfi, Adolpho José; Telles, E C C; Boullet, R; Valencia, E P E; Tomazello Filho, M (International Radiocarbon Conference, 1994)