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@article{PIM_1991_N_S_49_63_a1, author = {Mirko Lepovi\'c}, title = {On {Graphs} {Whose} {Energy} {Does} {Not} {Exceed} 4}, journal = {Publications de l'Institut Math\'ematique}, pages = {6 }, publisher = {mathdoc}, volume = {_N_S_49}, number = {63}, year = {1991}, url = {http://geodesic.mathdoc.fr/item/PIM_1991_N_S_49_63_a1/} }
Mirko Lepović. On Graphs Whose Energy Does Not Exceed 4. Publications de l'Institut Mathématique, _N_S_49 (1991) no. 63, p. 6 . http://geodesic.mathdoc.fr/item/PIM_1991_N_S_49_63_a1/