Hawkins, K. O. (1971). Parole selection: The American experience. University of Cambridge.
Lua i Stíl Chicago (17ú heag.)Hawkins, Keith Owen. Parole Selection: The American Experience. University of Cambridge, 1971.
Lua MLA (8ú heag.)Hawkins, Keith Owen. Parole Selection: The American Experience. University of Cambridge, 1971.
Rabhadh: Seans nach mbeach na luanna seo go hiomlán cruinn i ngach uile chás.