New Class of Quark Mass Matrices and the Flavor Mixing Matrix
  We discuss a new general class of mass matrix ansatz that respects the fermion mass hierarchy and calculability of the flavor mixing matrix. This is a generalization of the various specific forms of the mass matrix that is obtained by successive breaking of the maximal permutation symmetry. By confronting the experimental data, a large class of the mass matrices are shown to survive, while certain specific cases are phenomenologically ruled out. 
Kyungsik Kang and Sin Kyu Kang