Barretto, Mauro Pereira. 1963. “Diagncsis of Chronic Amebiasis. II. Comparative Study of the Efficiency of the Zinc Sulfate Centrifugal-Floatation Technic, in Successive Stool Specimens and of the Examination of Purged Stools, Used Either Separately or in Combination”. Revista Do Instituto De Medicina Tropical De São Paulo 5 (1): 1-11. https://revistas.usp.br/rimtsp/article/view/202337.