@book{9783925191657,
  title = {Der Brief als Problem der Edition},
  author = {Martin-M. Langner},
  publisher = {Frank \& Timme},
  year = {1970},
  edition = {1},
  url = {https://www.frank-timme.de/de/programm/produkt/der\_brief\_als\_problem\_der\_edition}
}