The Secret of Sigma Seven
Subtitle: Hardy Boys #110
Publisher: Aladdin
Published: October 1, 1991
Language: eng
Format: Paperback
Number of pages: 160
ISBN-13: 9780671727178
Subjects: Mystery and detective stories; Children's 9-12 - Fiction - Mysteries / Detective; Children: Grades 4-6; Mysteries, Espionage, & Detective Stories; Juvenile Fiction / Action & Adventure