BALL ROBERT. (1984). MANAGEMETN TECHNIQUES & QUANTITATIVE METHODS. HEINEMANN.
Lua i Stíl Chicago (17ú heag.)BALL ROBERT. MANAGEMETN TECHNIQUES & QUANTITATIVE METHODS. LONDON: HEINEMANN, 1984.
Lua MLA (9ú heag.)BALL ROBERT. MANAGEMETN TECHNIQUES & QUANTITATIVE METHODS. HEINEMANN, 1984.
Rabhadh: Seans nach mbeach na luanna seo go hiomlán cruinn i ngach uile chás.