@article{aler-et-al_ec2001,
  author       = {Aler, Ricardo and Borrajo, Daniel and Isasi, Pedro},
  journal      = {Evolutionary Computation},
  number       = 4,
  pages        = {387 -- 420},
  title        = {Learning to Solve Planning Problems Efficiently by Means of Genetic
    Programming},
  volume       = 9,
  year         = 2001,
}