deletions | additions       diff --git a/Payam.tex b/Payam.tex  index 094e54b..9f2c162 100644  --- a/Payam.tex  +++ b/Payam.tex 
...
\item Why does the hydrodynamic disturbance travel diffusively rather than at the sound speed?  \item Some reading about propagation of hydrodynamic information:\\  \citet{10.1103/PhysRevLett.70.1339} \citet{Ladd_1993}  short-time motion of colloidal particles: theory;\\ \citet{1995PhyA..214..185E},  \citet{Espanol_Rubio_Zuniga_1995} for discussion of how HD disturbances propagate and evidence for sound-waves;\\  \citet{Clercx_1997};\\