The Bi-Hamiltonian Structure of the Perturbation Equations of KdV   Hierarchy
  The bi-Hamiltonian structure is established for the perturbation equations of KdV hierarchy and thus the perturbation equations themselves provide also examples among typical soliton equations. Besides, a more general bi-Hamiltonian integrable hierarchy is proposed and a remark is given for a generalization of the resulting perturbation equations to $1+2$ dimensions. 
Wen-Xiu Ma and Benno Fuchssteiner (University of Paderborn)