@book{
title = {Geschichte des Mittelalters},
author = {},
editor = {Beloch, Karl Julius},
editor = {Pflugk-Harttung, Julius Albert Georg : von},
editor = {998072656808896 - Weltgeschichte - 2 -  },
editor = {Gotico },
year = {1910},
address = {Berlin },
publisher = {Ullstein & Co.},
}