@article{PORMA_2000__57_2_48773,
     author = {Wang, Genqiang and Yan, Jurang},
     title = {Existence theorem of periodic positive solutions for the {Rayleigh} equation of retarded type.},
     journal = {Portugaliae mathematica},
     pages = {153--160},
     publisher = {mathdoc},
     volume = {57},
     number = {2},
     year = {2000},
     zbl = {0963.34069},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/PORMA_2000__57_2_48773/}
}