TY  - GEN
AU  - Keyfitz, Barbara L.
AU  - Keyfitz,Barbara L.
AU  - Shearer,Michael
TI  - Nonlinear evolution equations that change type
T2  - The ima volumes in mathematics and its applications
SN  - 0387973532
U1  - 515.353 
PY  - 1990///
CY  - [S.l.]
PB  - Springer
ER  -