@misc{indiciae051d6f28c930,
  title = {Launch-period selection for the 1972 Venus launch opportunity.},
  author = {Fields, D. P. and Wilkinson, C. K., Jr.},
  year = {1969},
  url = {https://ntrs.nasa.gov/citations/19690061219},
  note = {Source identifier: 19690061219}
}