Possible textures of neutrino and charged lepton mass matrices
  We study a variety of different texture patterns in the basis in which the charged lepton mass matrix or neutrino mass matrix or neither are diagonal. The experimental results on the neutrinos provide sufficient restrictions to allow only a small number of simple patterns. We discuss particularly the texture zeroes which provide important relations among the mass eigenvalues and the mixing matrix. 
Bipin R. Desai, Utpal Sarkar and Alexander R. Vaucher