TY  - JOUR
AU  - W. R. Utz
TI  - Periodic solutions of $x" + f(x)x'^m + g(x) = 0$
JO  - Annales Polonici Mathematici
PY  - 1970
SP  - 327
EP  - 330
VL  - 24
IS  - 3
PB  - mathdoc
UR  - http://geodesic.mathdoc.fr/articles/10.4064/ap-24-3-327-330/
DO  - 10.4064/ap-24-3-327-330
LA  - en
ID  - 10_4064_ap_24_3_327_330
ER  -