@article{10_4064_cm108_2_6,
     author = {Jan Chabrowski and Bernhard Ruf},
     title = {On the critical {Neumann} problem
 with lower order perturbations},
     journal = {Colloquium Mathematicum},
     pages = {225--246},
     publisher = {mathdoc},
     volume = {108},
     number = {2},
     year = {2007},
     doi = {10.4064/cm108-2-6},
     language = {en},
     url = {http://geodesic.mathdoc.fr/articles/10.4064/cm108-2-6/}
}