Widdison, H. A. (1998). Social problems 98/99. Dushkin/McGraw-Hill.
Lua i Stíl Chicago (17ú heag.)Widdison, Harold A. Social Problems 98/99. Guilford, CT.: Dushkin/McGraw-Hill, 1998.
Lua MLA (8ú heag.)Widdison, Harold A. Social Problems 98/99. Dushkin/McGraw-Hill, 1998.
Rabhadh: Seans nach mbeach na luanna seo go hiomlán cruinn i ngach uile chás.