@misc{indiciaea8a2b721fdcf,
  title = {Negretti \& Zambra's encyclopædic illustrated and descriptive reference catalogue of optical, mathematical, physical, photographic and standard meteorological instruments, manufactured and sold by them — Illustration, Page 506},
  year = {1887},
  url = {https://www.biodiversitylibrary.org/page/16784344},
  note = {Source identifier: page-16784344}
}