Cita APA (7a ed.)
(1987). Birder's world. [Birder's World, Inc.].
Cita Chicago Style (17a ed.)
Birder's World. [Holland, MI]: [Birder's World, Inc.], 1987.
Cita MLA (9a ed.)
Birder's World. [Birder's World, Inc.], 1987.
Precaución: Estas citas no son 100% exactas.