Off-Shell Electromagnetic Form Fators of the Nucleon in Chiral   Perturbation Theory
  We study the electromagnetic form factors of a nucleon in next-to-leading order chiral perturbation theory (CPT) in the case where one of the nucleons is off its mass shell. We calculate the leading nonanalytic contributions to relevant measures for the off-shell dependence in the limited kinematical range allowed. 
J.W. Bos and J.H. Koch