According to Wick (1935), a proton may be dissociated into a neutron and an anti-electron for some fraction of the time, and therefore its magnetic moment can be given as:
According to Abraham Pais (1986), "This is the fundamentally correct explanation of the anomalous proton moment." - - - - - "Inward Bound," by Abraham Pais. In other words, Wick’s little-known theory of 1935, which treats protons as neutrons and anti-electrons, is the single explanation most correct in some fundamental way.
Information provided by: http://www.haberco.com