@techreport{KosterZymolka2004, author = {Arie M.C.A. Koster and Adrian Zymolka}, title = {Linear Programming Lower Bounds for Minimum Converter Wavelength Assignment in Optical Networks}, institution = {ZIB}, address = {Takustr. 7, 14195 Berlin}, number = {04-41}, language = {eng}, year = {2004} }