@article{10_21136_MB_2016_17,
     author = {Mawhin, Jean and Szyma\'nska-D\k{e}bowska, Katarzyna},
     title = {Couples of lower and upper slopes and resonant second order ordinary differential equations with nonlocal boundary conditions},
     journal = {Mathematica Bohemica},
     pages = {239--259},
     publisher = {mathdoc},
     volume = {141},
     number = {2},
     year = {2016},
     doi = {10.21136/MB.2016.17},
     mrnumber = {3499786},
     zbl = {06587864},
     language = {en},
     url = {http://geodesic.mathdoc.fr/articles/10.21136/MB.2016.17/}
}