Ruifang Liu Zhonghua Lu Jinlong Shu The minimal Laplacian spectral radius of trees with a given diameter. 78-83 2009 410 Theor. Comput. Sci. 1 http://dx.doi.org/10.1016/j.tcs.2008.09.060 db/journals/tcs/tcs410.html#LiuLS09