Guantao Chen George Davis Frank J. Hall Zhongshan Li Kinnari Patel Michael Stewart An Interlacing Result on Normalized Laplacians. 353-361 2004 18 SIAM J. Discrete Math. 2 http://dx.doi.org/10.1137/S0895480103438589 db/journals/siamdm/siamdm18.html#ChenDHLPS04