Dynamic Equilibria in Fluid Queuing Networks
  This paper continues the study of equilibria for flows over time in the fluid queueing model recently considered by Koch and Skutella [10]. We provide a constructive proof for the existence and uniqueness of equilibria in the case of a single origin-destination with piecewise constant inflow rates, through a detailed analysis of the static flows obtained as derivatives of a dynamic equilibrium. We also give a nonconstructive existence proof of equilibria when the inflow rates belong to $L^p$ including the extension to multiple origin-destinations. 
Roberto Cominetti, Jos\'e R. Correa, Omar Larr\'e
math.OC