TY  - BOOK
AU  - Ibragimov, Nail H.
AU  - Kovalev, Vladimir F.
TI  - Approximate and renormgroup symmetries
SN  - 9783642002274
U1  - 515.35 
PY  - 2009///
CY  - Berlin
PB  - Springer
KW  - Differential equations
ER  -