@article{PIM_1978_N_S_23_37_a5,
     author = {Drago\v{s} M. Cvetkovi\'c},
     title = {The {Main} {Part} {Of} {The} {Spectrum,} {Divisors} {And} {Switching} {Of} {Graphs}},
     journal = {Publications de l'Institut Math\'ematique},
     pages = {31 },
     publisher = {mathdoc},
     volume = {_N_S_23},
     number = {37},
     year = {1978},
     url = {http://geodesic.mathdoc.fr/item/PIM_1978_N_S_23_37_a5/}
}