Fonseca Almeida, Ariane, et al. “Adaptation of Ritchie Method for Diagnosing Helminthes and Protozoa in Samples of Sewage Silt With Chemical Substances Minimization”. O Mundo Da Saúde, vol. 33, no. 4, Oct. 2009, pp. 427-32, doi:10.15343/0104-7809.20094427431.