@book{1871,
	author = {Ryden, Barbara,},
	title = {Introduction to cosmology /},
	publisher = {Cambridge University Press,},
	year = {2017.},
	address = {New York, NY :},
	edition = {2/e},
	note = {Includes index.},
	url = {https://www.loc.gov/catdir/enhancements/fy1618/2016040124-b.html}
}