@misc{indiciaea9063b1f1e0b,
  title = {Singular extremals.},
  author = {Kelley, H. J. and Kopp, R. E. and Moyer, H. G.},
  year = {1967},
  url = {https://ntrs.nasa.gov/citations/19680043209},
  note = {Source identifier: 19680043209}
}