TY  - JOUR 
T1  - Adaptation of constant effort sampling and of removal trapping for the estimation of populations of microscopic organisms in dense substrates <sup>(</sup><sup>)</sup>
JO  - Acta Amazonica
A1  - Walker, Ilse
A1  - Lages, Maryolanda Trindade
SN  - 0044-5967
UL  - 10.1590/1809-43921980103535
VL  - 10 
Y1  - 1980
PB  - Brasil 
ER  -