@misc{indiciaeb825bf1f594a,
  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 491},
  year = {1887},
  url = {https://www.biodiversitylibrary.org/page/16784329},
  note = {Source identifier: page-16784329}
}