Playground and Recreation Association of America. The year book of the Playground and Recreation Association of America. Playground and Recreation Association of America.
Chicago-referens (17:e uppl.)Playground and Recreation Association of America. The Year Book of the Playground and Recreation Association of America. New York City: Playground and Recreation Association of America.
MLA-referens (8:e uppl.)Playground and Recreation Association of America. The Year Book of the Playground and Recreation Association of America. Playground and Recreation Association of America.
Varning: dessa hänvisningar är inte alltid fullständigt riktiga.