@misc{indiciae8f2c42bbfba3,
  title = {OPAD through 1991 - Status report no. 2},
  author = {Powers, W. T. and Cooper, A. E. and Wallace, T. L.},
  year = {1991},
  url = {https://ntrs.nasa.gov/citations/19930032412},
  note = {Source identifier: 19930032412}
}