@article{walker_lages_1980,  title={Adaptation of constant effort sampling and of removal trapping for the estimation of populations of microscopic organisms in dense substrates <sup>(</sup><sup>)</sup>},  volume={10},  ISSN={0044-5967},  url={https://doi.org/10.1590/1809-43921980103535},  DOI={10.1590/1809-43921980103535},  number={3},  journal={Acta Amazonica},  publisher={Instituto Nacional de Pesquisas da Amazônia},  author={Walker, Ilse and Lages, Maryolanda Trindade},  year={1980},  month={Sep},  pages={535–544} }