Flavia Bonomo Guillermo Durán Luciano N. Grippo Martín Darío Safe Partial Characterizations of Circular-Arc Graphs. 45-50 2008 30 Electronic Notes in Discrete Mathematics http://dx.doi.org/10.1016/j.endm.2008.01.009 db/journals/endm/endm30.html#BonomoDGS08