Charles Hodge (1855). “What is Presbyterianism?: An Address Delivered Before the Presbyterian Historical Society at Their Anniversary Meeting in Philadelphia, on Tuesday Evening, May 1, 1855”, p.60
David Brin, Matthew Woodring Stover (2013). “Star Wars on Trial: Science Fiction And Fantasy Writers Debate the Most Popular Science Fiction Films of All Time”, p.48, BenBella Books, Inc.