Lehman, J. A. (1991). Systems design in the fourth generation: Object-based development using dBase. Wiley.
Lua i Stíl Chicago (17ú heag.)Lehman, John A. Systems Design in the Fourth Generation: Object-based Development Using DBase. New York: Wiley, 1991.
Lua MLA (9ú heag.)Lehman, John A. Systems Design in the Fourth Generation: Object-based Development Using DBase. Wiley, 1991.
Rabhadh: Seans nach mbeach na luanna seo go hiomlán cruinn i ngach uile chás.