. "Electronic books"@en . . "Discusses the history of black holes, the scientific theory of how they are formed, and what they may be able to tell us about the future." . "Discusses the history of black holes, the scientific theory of how they are formed, and what they may be able to tell us about the future."@en . . . . . . . . . "Juvenile works" . "Juvenile works"@en . "Describes the characteristics and properties of black holes, and explains how black holes are studied today."@en . "Black holes" . "Black holes"@en . . .