Kirchshofer, R. (1968). The world of zoos: A survey and gazetteer. Batsford.
Lua i Stíl Chicago (17ú heag.)Kirchshofer, Rosl. The World of Zoos: A Survey and Gazetteer. London: Batsford, 1968.
Lua MLA (9ú heag.)Kirchshofer, Rosl. The World of Zoos: A Survey and Gazetteer. Batsford, 1968.
Rabhadh: Seans nach mbeach na luanna seo go hiomlán cruinn i ngach uile chás.