@article{ELA_2009__18__a5,
     author = {Liu, Bolian and Huang, Yufei and You, Zhifu},
     title = {On $\lambda_{1}$-extremal non-regular graphs},
     journal = {The electronic journal of linear algebra},
     pages = {735--744},
     publisher = {mathdoc},
     volume = {18},
     year = {2009},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/ELA_2009__18__a5/}
}