@article{10_4153_CMB_2011_138_3,
     author = {Kong, Qingkai and Wang, Min},
     title = {Eigenvalue {Approach} to {Even} {Order} {System} {Periodic} {Boundary} {Value} {Problems}},
     journal = {Canadian mathematical bulletin},
     pages = {102--115},
     year = {2013},
     volume = {56},
     number = {1},
     doi = {10.4153/CMB-2011-138-3},
     url = {http://geodesic.mathdoc.fr/articles/10.4153/CMB-2011-138-3/}
}