Halko, J. (1950). Religious census, District of Columbia: General summary. Washington Federation of Churches.
Lua i Stíl Chicago (17ú heag.)Halko, John. Religious Census, District of Columbia: General Summary. Washington, D.C.: Washington Federation of Churches, 1950.
Lua MLA (8ú heag.)Halko, John. Religious Census, District of Columbia: General Summary. Washington Federation of Churches, 1950.
Rabhadh: Seans nach mbeach na luanna seo go hiomlán cruinn i ngach uile chás.