@article{10_37236_718,
     author = {Steve Butler and Jason Grout},
     title = {A construction of cospectral graphs for the normalized {Laplacian}},
     journal = {The electronic journal of combinatorics},
     year = {2011},
     volume = {18},
     number = {1},
     doi = {10.37236/718},
     zbl = {1243.05144},
     url = {http://geodesic.mathdoc.fr/articles/10.37236/718/}
}