@techreport{SchiermeyerTuzaVoigt1997, author = {Ingo Schiermeyer and Zsolt Tuza and Margit Voigt}, title = {On-line rankings of graphs}, institution = {ZIB}, address = {Takustr. 7, 14195 Berlin}, number = {SC-97-32}, language = {eng}, year = {1997} }