@article{10_21136_CMJ_1973_101166,
     author = {Petzeltov\'a, Hana},
     title = {Periodic solutions of the equation $u_{tt}+u_{xxxx}=\varepsilon f(\cdot,\cdot,u,u_t)$},
     journal = {Czechoslovak Mathematical Journal},
     pages = {269--285},
     publisher = {mathdoc},
     volume = {23},
     number = {2},
     year = {1973},
     doi = {10.21136/CMJ.1973.101166},
     mrnumber = {0328286},
     zbl = {0263.35017},
     language = {en},
     url = {http://geodesic.mathdoc.fr/articles/10.21136/CMJ.1973.101166/}
}