@article{01484660,
title = {Existence theorem of periodic positive solutions for the Rayleigh equation of retarded type.},
journal = {Portugaliae Mathematica. Nova S\'erie},
volume = {57},
year = {2000},
pages = {153-160},
zbl = {0963.34069},
language = {en},
url = {http://dml.mathdoc.fr/item/01484660}
}
Wang, Genqiang; Yan, Jurang. Existence theorem of periodic positive solutions for the Rayleigh equation of retarded type.. Portugaliae Mathematica. Nova Série, Tome 57 (2000) pp. 153-160. http://gdmltest.u-ga.fr/item/01484660/