@misc{indiciaef59b1bb3433f,
  title = {Map of the Pittsburgh district showing railroad terminals and location of iron and steel works having track connections},
  author = {national tube co. engineering department and williams engraving co},
  year = {1906},
  url = {https://www.loc.gov/item/87693147/},
  note = {Source identifier: 87693147}
}