Igor Parfenoff Florian Roussel Irena Rusu Loose vertices in <i>C</i><sub>4</sub>-free Berge graphs. 137-160 2002 258 Discrete Mathematics 1-3 http://dx.doi.org/10.1016/S0012-365X(02)00267-4 db/journals/dm/dm258.html#ParfenoffRR02