@book {
	author = {Roger, Penrose},
	title = {Az idő ciklusai},
	year = {2017},
	publisher = {Akadémiai Kiadó},
	isbn = {978 963 454 035 9},
	doi = {10.1556/9789634540359},
	URL = {https://mersz.hu/kiadvany/234}
}