TY  - JOUR
AU  - Gião, António
TI  - On the origin of positive and negative electricity
JO  - Portugaliae mathematica
PY  - 1949
SP  - 143
EP  - 153
VL  - 8
IS  - 4
PB  - mathdoc
UR  - http://geodesic.mathdoc.fr/item/PORMA_1949__8_4_114681/
LA  - en
ID  - PORMA_1949__8_4_114681
ER  -