@article{10_37236_5933,
     author = {Fan Chung},
     title = {A generalized {Alon-Boppana} bound and weak {Ramanujan} graphs},
     journal = {The electronic journal of combinatorics},
     year = {2016},
     volume = {23},
     number = {3},
     doi = {10.37236/5933},
     zbl = {1339.05223},
     url = {http://geodesic.mathdoc.fr/articles/10.37236/5933/}
}