Gaya APA

Switzer, M., Kelsey, E. (s.a.). Nature's Children : Penguins & Elephants (--). New York: Scholastic Inc.

Gaya MLA

Switzer, Merebeth., Kelsey, Elin. "Nature's Children : Penguins & Elephants". -- New York: Scholastic Inc, s.a.. Text.