APA (7e ed.) Bronvermelding

Langdon-Dahm, M. (1986). Trade secrets: 25 proven success tools for working, dealing ... Learning development systems.

Chicago (17e ed.) Bronvermelding

Langdon-Dahm, Martha. Trade Secrets: 25 Proven Success Tools for Working, Dealing ... Dayton: Learning development systems, 1986.

MLA (9e ed.) Bronvermelding

Langdon-Dahm, Martha. Trade Secrets: 25 Proven Success Tools for Working, Dealing ... Learning development systems, 1986.