Genetic variation within the tupi linguistic group: new data on three amazonian tribes - Black, F L; Santos, S E; Salzano, F M; Callegar-Jacques, S M; Weiner, T A; Franco, M. H.; Hutz, M H; Rieger, T T; Kubo, R R; Mestriner, Moacyr Antonio (Annals of Human Biology, 1988)