Halko, J. (1950). Religious census, District of Columbia: General summary. Washington Federation of Churches.
Chicago-viite (17. p.)Halko, John. Religious Census, District of Columbia: General Summary. Washington, D.C.: Washington Federation of Churches, 1950.
MLA-viite (8. p.)Halko, John. Religious Census, District of Columbia: General Summary. Washington Federation of Churches, 1950.
Varoitus: Nämä viitteet eivät aina ole täysin luotettavia.