TY  - BOOK
AU  - Kryloff,N
AU  - Bogoliubov,N.N.
AU  - Lefschetz,Solomon
TI  - Introduction to non-linear mechanics
T2  - Annals of mathematics studies,
U1  - 515.35 18
PY  - 1947/// [Printing 1955]
CY  - Princeton
PB  - Princeton university press
KW  - Differential equations
KW  - Oscillations
ER  -