Ward, B. (1971). An urban planet? Girard Bank.
Lua i Stíl Chicago (17ú heag.)Ward, Barbara. An Urban Planet? [Philadelphia]: Girard Bank, 1971.
Lua MLA (8ú heag.)Ward, Barbara. An Urban Planet? Girard Bank, 1971.
Rabhadh: Seans nach mbeach na luanna seo go hiomlán cruinn i ngach uile chás.