Once again on molecular Brownian motion and related fundamental 1/f   noise: a logical analysis of exact equations
  The paper contains a simple semi-quantitative analysis of a structure of solution to the exact Bogolyubov functional equation for a particle interacting with ideal gas and driven by an external force, in comparison with solutions to model kinetic equations for the same system. It is shown that the exact equation inevitably predicts existence of significant 1/f-type fluctuations in mobility of the particle, and this result directly extends to particles in arbitrary fluid. 
Yu.E.Kuzovlev
cond-mat.stat-mech math-ph math.MP