@book { NachhaltigeErnhrunginSingleHaushalten, title = "Nachhaltige Ernährung in Single-Haushalten", author = "Kristina {Bergmann}", year = "2006", publisher = "GRIN Verlag", address = "München, Germany", doi = "10.3239/9783638564649", url = "https://www.hausarbeiten.de/document/63402" }