@misc{indiciae8adb97ade78b,
  title = {Shape from shading in different frames of reference.},
  author = {I P Howard and S S Bergström and M Ohmi},
  year = {1990},
  doi = {10.1068/p190523},
  url = {https://pubmed.ncbi.nlm.nih.gov/2096370/},
  note = {Source identifier: 2096370}
}