TY  - DATA
AU  - Loud, W. S.
TI  - Periodic solutions of perturbed second-order autonomous equations 
T2  - Memoirs of the American Mathematical Society, 
SN  - 9780821899915 (online)
PY  - 1964///
CY  - Providence, R.I.
PB  - American Mathematical Society
UR  - http://www.ams.org/memo/0047
ER  -