Gray, W. B. (1986). Productivity versus OSHA and EPA regulations. Michigan: Umi Reseach Press.
Dyfyniad Arddull ChicagoGray, Wayne B. Productivity Versus OSHA and EPA Regulations. Michigan: Umi Reseach Press, 1986.
Dyfyniad MLAGray, Wayne B. Productivity Versus OSHA and EPA Regulations. Michigan: Umi Reseach Press, 1986.
Rhybudd: Mae'n bosib nad yw'r dyfyniadau hyn bob amser yn 100% cywir.