@Article{ 
  ste01,
  author = { Stepanov, Eugene },
  title = { Relaxation of optimal control problems with shifted controls },
  journal = { J. Nonlinear and Convex Anal. },
  year = { 2002 },
  volume = { 3 },
  number = { 2 },
  pages = { 207-230 },
  URL = { http://cvgmt.sns.it/paper/82/ },
  note = { cvgmt preprint}
}