@article{10_1007_s10492_008_0014_0,
     author = {Liu, Jin-Zhi and Jiang, Zhi-Yuan and Wu, Ai-Xiang},
     title = {The existence of periodic solutions for a class of nonlinear functional differential equations},
     journal = {Applications of Mathematics},
     pages = {97--103},
     publisher = {mathdoc},
     volume = {53},
     number = {2},
     year = {2008},
     doi = {10.1007/s10492-008-0014-0},
     mrnumber = {2399900},
     zbl = {1199.34351},
     language = {en},
     url = {http://geodesic.mathdoc.fr/articles/10.1007/s10492-008-0014-0/}
}