@book{Ratzel+1921,
url = {https://doi.org/10.1515/9783112342541},
title = {Deutschland},
title = {Einführung in die Heimatkunde},
author = {Friedrich Ratzel},
publisher = {De Gruyter},
address = {Berlin, Boston},
doi = {doi:10.1515/9783112342541},
isbn = {9783112342541},
year = {1921},
lastchecked = {2026-05-09}
}