@misc{indiciae9185e1db7f3e,
  title = {Necessary and sufficient conditions for optimality for singular control problems - A limit approach},
  author = {Jacobson, D. H. and Speyer, J. L.},
  year = {1971},
  url = {https://ntrs.nasa.gov/citations/19710051203},
  note = {Source identifier: 19710051203}
}