TY  - JOUR 
T1  - 2d Gravity with torsion, oriented matroids and 2+2 dimensions
JO  - Brazilian Journal of Physics
A1  - Nieto, J.A.
A1  - León, E.A.
SN  - 0103-9733
UL  - 10.1590/S0103-97332010000400004
VL  - 40 
Y1  - 2010
PB  - Brasil 
ER  -