An Exactly Solvable Model of Interacting Bosons
  We introduce a class of exactly solvable boson models. We give explicit analytic expressions for energy eigenvalues and eigenvectors for an sd-boson Hamiltonian, which is related to the SO(6) chain of the Interacting Boson Model Hamiltonian. 
A.B. Balantekin, T. Dereli, and Y. Pehlivan