@book{90919,
	author = {Haeckel, Ernst, and Neumann, Carl W.},
	title = {Natur und Mensch :},
	publisher = {Project Gutenberg,},
	year = {2015},
	address = {Salt Lake City, UT :},
	note = {Release date is 2015-09-30},
	url = {https://www.gutenberg.org/ebooks/50081}
}