Integrable generalizations of the two new soliton hierarchies of AKNS   and KN types associated with $so(3,\mathbb{R})$
  The two matrix spectral problems of Ablowitz-Kaup-Newell-Segur (AKNS) and Kaup-Newell (KN) types associated with so(3,R) are generalized. The corresponding hierarchies of generalized soliton equations are derived by the standard procedure using the zero curvature formulation. Recursion operators and bi-Hamiltonian structures are explicitly constructed for the resulting two generalized soliton hierarchies of AKNS and KN types, which shows their Liouville integrability. 
Chun-Xia Li, Shou-Feng Shen, Wen-Xiu Ma and Shui-Meng Yu
nlin.SI