Tamar Eilam Shlomo Moran Shmuel Zaks Approximation Algorithms for Survivable Optical Networks. 104-118 http://link.springer.de/link/service/series/0558/bibs/1914/19140104.htm 2000 conf/wdag/2000 DISC db/conf/wdag/disc2000.html#EilamMZ00