Less Singular Terms and Small x Evolution in a Soluble Model
  We calculate the effect of the less singular terms at small x on the evolution of the coefficient function in \phi^3 theory in six dimensions, which result from a complete solution of the ladder equation. Scale-invariant next-to-leading order contributions are also studied. We show that the small x approximation does not deliver the dominant contributions. 
J. Bl\"umlein and W.L. van Neerven