The Linearity of the Cosmic Expansion Field and the Value of the Hubble   Constant
  A linearity test shows H_0 to decrease by 7% out to 18000 km/s. The value at 10000 km/s is a good approximation to the mean value of Ho over very large scales. The construction of the extragalactic distance scale is discussed. Field galaxies, cluster distances relative to Virgo, and blue supernovae of type Ia yield Ho(cosmic) with increasing weight; they give consistently H_0=57+/-7 (external error). This value is supported by purely physical distance determinations (SZ effect, gravitational lenses, MWB fluctuations). Arguments for H_0>70 are discussed and shown to be flawed. 
G.A. Tammann (Astron. Inst., Univ. Basel)