@misc{indiciae848bcb5b5e2c,
  title = {Deposits of manganese ore in Costa Rica. Deposits of manganese ore near Boqueron River, Panama},
  author = {Julian Ducker Sears},
  year = {1920},
  doi = {10.3133/b710c},
  url = {https://pubs.usgs.gov/publication/b710C},
  note = {Source identifier: b710C}
}