APA
Sundgaard A., illustrated by Eric Carle, .The Lamb and the Butterfly. : .
Chicago
Sundgaard Arnold, illustrated by Eric Carle, .The Lamb and the Butterfly. : .
Harvard
Sundgaard A., illustrated by Eric Carle, .The Lamb and the Butterfly. : .
MLA
Sundgaard Arnold, illustrated by Eric Carle, .: . .