@article{EJDE_2002__2002__a245,
     author = {Karakostas, G.L. and Tsamatos, P.Ch.},
     title = {Positive solutions and nonlinear eigenvalue problems for retarded second order differential equations},
     journal = {Electronic Journal of Differential Equations},
     publisher = {mathdoc},
     volume = {2002},
     year = {2002},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/EJDE_2002__2002__a245/}
}