Measurement of HERA's Central RF Frequency       398
  G.H. Hoffstaetter, B. Holzer, F. Willeke, DESY, Hamburg; A. Meseck, HMI, Berlin      
  PAPER        
       
  Measurement of Optical Functions in HERA       1130
  W. Decking, B. Holzer, J. Keil, T. Limberg, DESY, Hamburg      
  PAPER