Minimal Radiative Neutrino Mass Mechanism for Inverse Seesaw Models
  We study a minimal one-loop radiative mechanism for generating small Majorana neutrino masses in inverse seesaw extensions of the Standard Model with two singlet fermions per family. The new feature of this radiative mechanism is that the one-loop induced left-handed neutrino mass matrix is directly proportional to the Majorana mass matrix of the right-handed neutrinos. This is a very economical scenario without necessitating the existence of non-standard scalar or gauge fields. 
P. S. Bhupal Dev, Apostolos Pilaftsis
hep-ph