TY  - JOUR 
T1  - Comparing the Mori formalism and the green function methods
JO  - Brazilian Journal of Physics
A1  - Pires, A.S.T.
A1  - Gouvêa, M.E.
SN  - 0103-9733
UL  - 10.1590/S0103-97332004000600009
VL  - 34 
Y1  - 2004
PB  - Brasil 
ER  -