One aspect of the Gold article that I particularly like is that it shows  
that the arguments for economies and diseconomies of scale that one usually  
encounters are ad hoc and intended to provide a U-shape to the long run cost  
curve--a shape without which the perfectly competitive firm would have no  
long-run equilibrium.  The needs of model-building driving an argument seems  
a bit backward.  
  
Samuel Bostaph