References for Ranging and Differenced Range ("Doppler) Observations to the Viking and Pathfinder Landers

  Folkner,W.F., Yoder,C.F., Yuan,D.N., Standish,E.M. and Preston,R.A.:
  1998, "Interior Structure and Seasonal Mass Redistribution of Mars
  from Radio Tracking of Mars Pathfinder", Science, 278, 1749-1752.