Langdon-Dahm, M. (1986). Trade secrets: 25 proven success tools for working, dealing ... Learning development systems.
Lua i Stíl Chicago (17ú heag.)Langdon-Dahm, Martha. Trade Secrets: 25 Proven Success Tools for Working, Dealing ... Dayton: Learning development systems, 1986.
Lua MLA (9ú heag.)Langdon-Dahm, Martha. Trade Secrets: 25 Proven Success Tools for Working, Dealing ... Learning development systems, 1986.
Rabhadh: Seans nach mbeach na luanna seo go hiomlán cruinn i ngach uile chás.