APA
Keene Carolyn, . (1980). The Flying Saucer Mystery. New york: Penguin group.
Chicago
Keene Carolyn, . 1980. The Flying Saucer Mystery. New york: Penguin group.
Harvard
Keene Carolyn, . (1980). The Flying Saucer Mystery. New york: Penguin group.
MLA
Keene Carolyn, . The Flying Saucer Mystery. New york: Penguin group. 1980.