@booklet {8520,
	title = {Invisible Barriers},
	year = {1958},
	month = {1958},
	publisher = {Avalon Books. },
	address = {New York},
	abstract = {<p>Dystopia of a world where all countries have cut themselves off from each other.</p>},
	keywords = {Male author, US author},
	author = {[Robert] [Silverberg] (b. 1935)}
}
