TY  - JOUR 
T1  - Biomphalaria obstructa (Morelet, 1849): a study of topotypic specimens (Mollusca: pulmonata: planorbidae)
JO  - Memórias do Instituto Oswaldo Cruz
A1  - Paraense, W. Lobato
SN  - 0074-0276
UL  - 10.1590/S0074-02761990000400002
VL  - 85 
Y1  - 1990
PB  - Brasil 
ER  -