A comparison of rating scale, secondary-task, physiological, and primary-task workload estimation techniques in a simulated flight task emphasizing communications load.

@article{Casali1983ACO,
  title={A comparison of rating scale, secondary-task, physiological, and primary-task workload estimation techniques in a simulated flight task emphasizing communications load.},
  author={John G. Casali and Walter W. Wierwille},
  journal={Human factors},
  year={1983},
  volume={25 6},
  pages={623-41}
}