Leaching techniques on sedimentary and low grade metamorphic rocks: a review, recent results and some perspectives - Kawashita, Koji; Macedo, M. H. F.; Thomaz Filho, Antonio; Babinski, Marly; Odo, Marisa Yukie Kawashita; Petronilho, Liliane Aparecida; Sato, Kei (South American Symposium on Isotope Geology, 1997)