Si-Qing Zheng Maximum independent sets of circular-arc graphs: Simplified algorithm and proofs. 15-19 1996 28 Networks 1 http://dx.doi.org/10.1002/(SICI)1097-0037(199608)28:1<15::AID-NET3>3.0.CO;2-G db/journals/networks/networks28.html#Zheng96