Frahm, R., & Covington, J. (1979). What's happening in minimum competency testing. Phi Delta Kappa.
Lua i Stíl Chicago (17ú heag.)Frahm, Robert, agus Jimmie Covington. What's Happening in Minimum Competency Testing. Bloomington, Ind.: Phi Delta Kappa, 1979.
Lua MLA (8ú heag.)Frahm, Robert, agus Jimmie Covington. What's Happening in Minimum Competency Testing. Phi Delta Kappa, 1979.
Rabhadh: Seans nach mbeach na luanna seo go hiomlán cruinn i ngach uile chás.