@book
{TN_libero_mab2,
author = {
Humboldt, Wilhelm von
Leitzmann, Albert
},
title = {
Wilhelm von Humboldts Briefe an eine Freundin
},
publisher = {Insel-Verl.},
year = {19XX-},
address = {
Leipzig
},
url = {
http://slubdd.de/katalog?TN_libero_mab2
}
}