Simple Formula for Nuclear Charge Radius
  A new formula for the nuclear charge radius is proposed, dependent on the mass number (A) and neutron excess (N-Z) in the nucleus. It is simple and it reproduces all the experimentally available mean square radii and their isotopic shifts of even--even nuclei much better than other frequently used relations. 
B. Nerlo-Pomorska and K. Pomorski (The Maria Curie-Sklodowska   University, Lublin, Poland)