@article{10_1017_S0017089509990346,
     author = {KYRITSI, SOPHIA TH. and PAPAGEORGIOU, NIKOLAOS S.},
     title = {ON {THE} {MULTIPLICITY} {OF} {SOLUTIONS} {FOR} {NON-LINEAR} {PERIODIC} {PROBLEMS} {WITH} {THE} {NON-LINEARITY} {CROSSING} {SEVERAL} {EIGENVALUES}},
     journal = {Glasgow mathematical journal},
     pages = {271--302},
     year = {2010},
     volume = {52},
     number = {2},
     doi = {10.1017/S0017089509990346},
     url = {http://geodesic.mathdoc.fr/articles/10.1017/S0017089509990346/}
}