Westerman, M. D. (1993). The business environmental handbook. The Oasis Press/PSI Research.
Dyfyniad Arddull ChicagoWesterman, Martin D. The Business Environmental Handbook. Grants Pass, Oregon: The Oasis Press/PSI Research, 1993.
Dyfyniad MLAWesterman, Martin D. The Business Environmental Handbook. The Oasis Press/PSI Research, 1993.
Rhybudd: Mae'n bosib nad yw'r dyfyniadau hyn bob amser yn 100% cywir.