Light Front Cloudy Bag Model: Nucleon Electromagnetic Form Factors
  The nucleon is modeled, using light front dynamics, as a relativistic system of three bound constituent quarks emersed in a cloud of pions. The pionic cloud is important for understanding low-momentum transfer physics, especially the neutron charge radius, but the quarks are dominant at large momentum transfer. The model achieves a very good description of existing data for the four electromagnetic elastic form factors. 
Gerald A. Miller