@article{11311_752618,
  author    = {Topputo, Francesco and Bernelli Zazzera, Franco},
  title     = {Approximate Solutions to Nonlinear Optimal Control Problems in Astrodynamics},
  year      = {2013},
  doi       = {10.1155/2013/950912},
  journal   = {ISRN AEROSPACE ENGINEERING},
  volume    = {2013},
  pages     = {1--7},
}