Measurements of group velocity of light in the lake Baikal water
  The results of direct measurements of group velocity of light in the lake Baikal water at the depth of 1100 m are presented. The lake Baikal water dispersion has been measured at three wavelengths: 370 nm, 470 nm and 525 nm. The results are in a rather good agreement with theoretical predictions. 
B.K. Lubsandorzhiev, P.G. Pokhil, R.V. Vasiliev, Y.E. Vyatchin