@article {ekim2008polarity, title = {Polarity of chordal graphs}, journal = {Discrete Applied Mathematics}, volume = {156}, number = {13}, year = {2008}, pages = {2469{\textendash}2479}, publisher = {Elsevier}, author = {Ekim, Tinaz and Hell, Pavol and Stacho, Juraj and de Werra, Dominique} }