TY  - BOOK
AU  - edited by Lefschetz, S.
TI  - Contribution to the theory of nonlinear oscillations
SN  - 9780691079318
U1  - 517.912 
PY  - 1950///
CY  - Princeton
PB  - PUP
KW  - MATHEMATICS
KW  - NONLINEAR OSCILLATIONS
ER  -