@book{112380,
	author = {Hubble, Edwin,},
	title = {Photographic investigations of faint nebulae},
	publisher = {Project Gutenberg,},
	year = {2023},
	series = {Publications of the Yerkes Observatory, volume IV part II},
	address = {Salt Lake City, UT :},
	note = {Release date is 2023-09-15},
	url = {https://www.gutenberg.org/ebooks/71654}
}