Primary glomerular diseases in Brazil (1979-1999): is the frequency of focal and segmental glomerulosclerosis increasing? - Oliveira, M. Bahiense; Saldanha, Luís Balthazar; Mota, E. L. Andrade; Penna, Decio de Oliveira; Barros, R. Toledo; Romão Junior, J. E. (Clinical Nephrology, 2004)