@misc{indiciaefb9590db11aa,
  title = {Phase contrast and interference microscopy with the electron microscope.},
  author = {P N Unwin},
  year = {1971},
  doi = {10.1098/rstb.1971.0039},
  url = {https://pubmed.ncbi.nlm.nih.gov/4399209/},
  note = {Source identifier: 4399209}
}