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@article{PIM_1985_N_S_38_52_a5, author = {Mieczyslaw Borowiecki}, title = {On {Spectrum} and {Per-spectrum} of {Graphs}}, journal = {Publications de l'Institut Math\'ematique}, pages = {31 }, publisher = {mathdoc}, volume = {_N_S_38}, number = {52}, year = {1985}, language = {en}, url = {http://geodesic.mathdoc.fr/item/PIM_1985_N_S_38_52_a5/} }
Mieczyslaw Borowiecki. On Spectrum and Per-spectrum of Graphs. Publications de l'Institut Mathématique, _N_S_38 (1985) no. 52, p. 31 . http://geodesic.mathdoc.fr/item/PIM_1985_N_S_38_52_a5/