References
- Atslega , S. 2007 . Multiplicity results for the Neumann boundary value problem . Mathematical Modelling and Analysis , 12 (2) : 179 – 186 .
- Burton , T.A. 1991 . The nonlinear wave equation as a Liénard equation . Funkcialaj Ekvacioj , 34 : 529 – 545 .
- Hara , T. and Yoneyama , T. 1988 . On the global center of generalized Liénard equation and its application to stability problems II . Funkcialaj Ekvacioj , 3 (2) : 221 – 225 .
- Ogorodnikova , S. and Sadyrbaev , F. 2005 . Estimations of the number of solutions to some nonlinear second order boundary value problems . Mathematics. Differential Equations (Univ. of Latvia, Institute of Math. and Comp. Sci. , 5 : 24 – 32 . (available electronically at http://www.lumii.lv/math.htm)
- Sabatini , M. 2004 . On the period function of x'' + f(x)x'2 + g(x) = 0 . Diff. Equations , 196 : 151 – 168 .
- Sakata , S. 1994 . On the existence of periodic solutions of a Lienard system . Funkcialaj Ekvacioj , 37 (1) : 155 – 174 .
- Sansone , G. 1954 . Ordinary Differential Equations, II , Moscow : Izdatelstvo Inostrannoi Liter‐atury . (in Russian)
- This work is supported by the project VPD1/ESF/PIAA/04/NP/3.2.3.1/0003/0065