@book{7541381,
	author = {Фрейденталь, Х. and Петров, Ю.А.},
	title = {Язык логики},
	publisher = {Наука},
	year = {1969},
	address = {Москва},
	note = {На обороте тит. л.: The language of logic. By Hans Freudenthal}
}