Systematic analysis of \Delta I = 4 bifurcation in A~150 superdeformed   nuclei: Active orbitals
  A simple criterion for the \Delta I = 4 bifurcation is applied to thirty superdeformed bands in the A~150 mass region. The analysis allows to differentiate between active and inactive for staggering single-particle states. The consideration is based on additivity of nonaxial hexadecapole moment, which plays a key role in the phenomenon. 
Igor Pavlichenkov and Andrei Shchurenkov (Russian Research Center   "Kurchatov Institute")