@misc{indiciae467dcc19fdda,
  title = {Systematic notes on Palearctic birds. No. 52, Supplementary notes on Bubo bubo / American Museum novitates — Illustration, Page 8},
  year = {1963},
  url = {https://www.biodiversitylibrary.org/page/62833789},
  note = {Source identifier: page-62833789}
}