@book {73332,
	title = {Philosophy of natural science},
	year = {1966},
	pages = {116},
	publisher = {Prentice-Hall},
	organization = {Prentice-Hall},
	url = {https://books.google.com/books?id=Iau78s98cqwC\&pgis=1},
	author = {Hempel, Carl Gustav}
}
