Walsh, J. E. (1968). Principles of data processing. Pitman.
Lua i Stíl Chicago (17ú heag.)Walsh, J. E. Principles of Data Processing. Toronto: Pitman, 1968.
Lua MLA (8ú heag.)Walsh, J. E. Principles of Data Processing. Pitman, 1968.
Rabhadh: Seans nach mbeach na luanna seo go hiomlán cruinn i ngach uile chás.