@article{AlLeGuGrNe01a,
  author=       {Natalia M. Alexandrov and Robert Michael Lewis and 
                 Clyde R. Gumbert and Lawrence L. Green and Perry A. Newman},
  title=        {Approximation and Model Management in Aerodynamic
                 Optimization With Variable-Fidelity Models},
  journal=      {Journal of Aircraft},
  volume=       {38},
  number=       {6},
  month=        {November--December},
  year=         {2001},
  pages=        {1093--1101}
}