Reader's Digest Association. (1996). Great mysteries of the 20th century. Reader's Digest.
Citazione stile Chigago Style (17a edizione)Reader's Digest Association. Great Mysteries of the 20th Century. Pleasantville: Reader's Digest, 1996.
Citatione MLA (9a ed.)Reader's Digest Association. Great Mysteries of the 20th Century. Reader's Digest, 1996.
Attenzione: Queste citazioni potrebbero non essere precise al 100%.