TY  - GEN
AU  - Stephani,Hans
AU  - Hans,Stephani
AU  - MacCallum,Malcolm
TI  - Differential Equations :their solution using symmetries
T2  - Cambridge monographs on mathematical physics
SN  - 0521355311
U1  - 515.35 
PY  - 1989///
CY  - New york
PB  - Cambridge University Press
ER  -